Self-capacitance of nanosized objects

A method to determine the effective self-capacitance of atomic and molecular objects is proposed. Experimental data and the results of quantum-mechanical computations are used to calculate the self-capacitance of atoms and various molecules. It is demonstrated that the self-capacitance is predominantly determined by the topology of the nanoobject rather than its chemical composition. The notion of the effective self-capacitance makes it possible to establish a relation of the chemical parameters of atoms and molecules and the electric parameters of molecular electronic devices.     

Permalloy thin-film inductors

The design of an integrated thin-film inductor suitable for use at 10 MHz is described, and some operational characteristics are given. The inductor has the shape of a square spiral and is surrounded by permalloy thin films according to a certain pattern. This pattern allows these films to be driven in the hard direction and thus utilises the hard-direction permeability which is quite large (?2700).     

Design of microfabricated inductors

Possible configurations for microfabricated inductors are considered. Inductance can be set by adjusting permeability through control of anisotropy of a permalloy core or via a patterned quasi-distributed gap. A design methodology based on a simple model is proposed. A more accurate model and a numerical optimization are also developed. Design examples for 5- and 10-MHz buck converters and 2.5-MHz resonant converter applications are presented     

变压器和电感器

可承载40A的自屏蔽SMT电感器 HM73系列钼铁镍合金粉末自屏蔽SMT电感器从0.1～8.2μH有16种额定值,最高可承受40A和400μJ/cm~3。它们是用导体密度比圆形导线高20％的超薄矩形导线制造的,它们还具有0.08～15.2mΩ的DCR。     

Self-assembled screen-printed microwave inductors

The fabrication and measured performance of a self-assembled microwave inductor, created using a novel screen-printing technology, is reported for the first time. Real surface micromachining is performed using screen printing, by introducing a unique sacrificial layer. The self-assembled inductor demonstrated a significantly increased unloaded Q-factor and first self-resonant frequency.     

Digital inductors and capacitors

Circuits are described for simulating inductors and capacitors by digital (hardware) techniques. Filter and oscillator applications are discussed and test results are given.     

SMPS功率电感器的选择

开关模式电源(SMPS)功率电感器的选择过程绝非是信手拈来那么简单,必须要对对实际电感器有充分的了解。SMPS的选用要求包括:大功率、小尺寸、高开关频率和高效率。此外,考虑到健康、环保方面的因素,很多用户还提出了降低电磁辐射(EMI)的要求。理想的电感器选择除了取决于对实际电感器(并不完善的)特性的了解之外,还需要对完善的电感器特性有一定的通晓。储能方面的考虑14种基本的SMPS设计大多依靠电感器来进行储能和EMI抑制(滤波)。控制电路负责对储存的能量进行调节,并通过将电感器与电源相连的方法来增加能量的存储。存储在一个电…     

High-Q factor three-dimensional inductors

In this paper, the great flexibility of three-dimensional (3-D) monolithic-microwave integrated-circuit technology is used to improve the performance of on-chip inductors. A novel topology for high-Q factor spiral inductor that can be implemented in a single or multilevel configuration is proposed. Several inductors were fabricated on either silicon substrate (/spl rho/ = 30 /spl Omega/ /spl middot/ cm) or semi-insulating gallium-arsenide substrate demonstrating, more particularly, for GaAs technology, the interest of the multilevel configuration. A 1.38-nH double-level 3-D inductor formed on an Si substrate exhibits a very high peak Q factor of 52.8 at 13.6 GHz and a self-resonant frequency as high as 24.7 GHz. Our 4.9-nH double-level GaAs 3-D inductor achieves a peak Q factor of 35.9 at 4.7 GHz and a self-resonant frequency of 8 GHz. For each technology, the performance limits of the proposed inductors in terms of quality factor are discussed. Guidelines for the optimum design of 3-D inductors are provided for Si and GaAs technologies.     

Simulated inductors using differential amplifiers

A novel circuit for the simulation of high-quality inductors is described. The circuit is based on differential amplifiers and can use standard integrated circuits; in initial tests, it has given very large effective inductances with high Qfactors at very low frequencies.     

High-performance inductors on plastic substrate

Wafer-transfer technology (WTT) has been applied to transfer RF inductors from a silicon wafer to an opaque plastic substrate (FR-4). By completely eliminating silicon substrate, the high performance of integrated inductors (Q-factor > 30 for inductance /spl sim/3 nH with resonant frequency /spl sim/23 GHz) has been achieved. Based on the analysis of a modified /spl pi/-network model, our results suggest that the performance limitation is switched from being a synthetic mechanism of substrate and metal-ohmic losses on low resistivity Si-substrate to merely a metal-ohmic loss on FR-4. Thus, the inductor patterns, which are optimized currently for RFICs on silicon wafer, can be further optimized to take full advantage of the WTT on new substrate from the newly obtained design freedom.     

Alternative realisations of switched-capacitor floating inductors

Several switched-capacitor circuits simulating grounded and floating inductors have been published recently. Several alternative realizations are presented of s.c. inductors using one operational amplifier, which can be derived from a configuration reported previously.     

Flip chip assembled MEMS inductors

High performance suspended MEMS inductors produced using a flip chip assembly approach are described. An inductor structure is fabricated on a carrier and then flip chip assembled onto a substrate to form a suspended inductor for RF-IC applications with significant improvement in Q-factor and frequency of operation over the conventional IC inductors. A spiral MEMS inductor has been successfully produced on a silicon substrate with an air gap of 26 /spl mu/m between the inductor structure and the substrate. The inductance of the device was measured to be /spl sim/2 nH and a maximum Q-factor of 19 at /spl sim/2.5 GHz was obtained after pad/connector de-embedding.     

New tunable synthetic floating inductors

Three new active RC synthetic floating inductance circuits are proposed which realise lossless f.i. and series and parallel RL impedance, respectively employing three and two second-generation current conveyors as active elements. The novel features of the new circuits are that (i) in contrast to available operational-amplifier circuits for f.i.s, the circuits presented here do not require component matching for the desired realisation; (ii) the new circuits employ a minimum possible number of passive elements (only two resistors and a capacitor); (ii) in all the new circuits, the inductance value is independently controllable through a single resistance.     

Self resonance in foil inductors

Coils having aluminium-foil windings exhibit multiple self-resonant behaviour in the range 0.5?20 MHz. The dependence of resonance frequencies on number of turns is reported, and a lumped circuit model which accounts approximately for the effects is presented.     

Improved performance of Si-based spiral inductors

Conventional spiral inductors on silicon wafer have suffered low quality (Q) factor due to substrate loss. In this work, a technique that combines optimized shielding poly and proton implantation treatment is utilized to improve inductor Q-value. The optimized poly-silicon and proton-bombarded substrate have added 37% and 54% increment to the Q-value of inductors, respectively. If two techniques are combined, a phenomenal Q-value increment as high as 122% of 4-nH spiral inductors can be realized. The combination of the two means has created a multiplication of their individual contribution rather than addition. The technique used in this work shall become a critical measure to put inductors on silicon substrate with satisfactory performance for Si-based radio frequency integrated circuit applications.     

Thin-film superconducting inductors for power electronics

Superconducting thin-film inductors promise to be key elements in high-frequency, high-power density, high-efficiency power supplies. A thin-film (0.6 μm-thick) YB₂Cu₃O₇ inductor capable of handling currents up to 12 A DC was found to have a Q value of 1300 at 260 MHz and 77 K, a factor of 20 higher than an identical inductor made of 15 μm thick Cu; this improvement factor is shown to be >64 at lower frequencies (a few MHz)     

不需要耦合电感器的Hartley振荡器

检查一个传统的Hartley振荡器电路就会注意到它的标志:一个带抽头的电感器,它用于确定振荡频率,并提供维持振荡的反馈.尽管可以方便地计算出某个额定频率所需的总感量,但要找到耦合系数k仍有很高技术难度,并且可能需要进行实验优化,也归为"分割试验"法.本设计实例给出了另一种替代等效电路,能在建立原型电路以前做出电路模型.     

Design optimization of switchable multi-port spiral inductors

In this paper, we develop a design optimization methodology for switchable multi-port spiral inductors in fully integrated wireless systems. The methodology simultaneously maximizes the inductor’s performance for multiple inductance values and operating frequencies. We utilize multi-level optimization techniques to efficiently design the geometry of the switchable inductor structure. The methodology can produce designs with significantly larger quality factors than those obtained by optimizing the inductor design for a single inductance value and operating frequency.     

Physical modeling of spiral inductors on silicon

This paper presents a physical model for planar spiral inductors on silicon, which accounts for eddy current effect in the conductor, crossover capacitance between the spiral and center-tap, capacitance between the spiral and substrate, substrate ohmic loss, and substrate capacitance. The model has been confirmed with measured results of inductors having a wide range of layout and process parameters. This scalable inductor model enables the prediction and optimization of inductor performance