Vertical Solenoid Research Articles

Design and Analysis of Simultaneous Wideband Input/Output Matching Technique for Ultra-Wideband Amplifier

A simultaneous wideband input/output matching technique for ultra-wideband (UWB) low-noise amplifier (LNA) is proposed in this paper. Feedback resistors leading the gate inductors combined with inductive dividers at output ports achieve an extended bandwidth and good input/output return loss. Moreover, Q-factor improved vertical solenoid inductors are used in the matching networks for high gain and low noise figure (NF). The proposed matching technique, not only enhances the bandwidth, but also achieves a high gain and a low NF for the fabricated 3.1-10.6-GHz monolithic 180-nm CMOS UWB amplifier. Operating at low supply voltage, the measured power consumption is 18.9 mW, the measured gain of the UWB LNA is 15.02 dB, and the NF is 3.1 dB. Moreover, the measured input/output reflection coefficients S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> are lower than -9.4 dB and -15.8 dB, respectively, covering the full-band UWB frequencies. Compared to previously published full-band 3.1-10.6-GHz 180-nm CMOS UWB LNAs, the proposed LNA measurements demonstrate high gain, low NF, low supply voltage, low power dissipation, and good input/output reflection coefficients.

Magnetic-Thermal-Fluidic Analysis for Cooling Performance of Magnetic Nanofluids Comparing With Transformer Oil and Air by Using Fully Coupled Finite Element Method

Magnetic-thermal-fluidic analyses were conducted to assess the cooling performance of magnetic nanofluids by comparing the performance with that of transformer oil and air using the fully coupled finite element method (FEM) considering the magnetoconvection phenomena. Magnetic nanofluids (MNFs) have been studied extensively for bio- and nanotechnology applications. In particular, some studies reported that the MNF has good characteristics for thermal management and electric insulation in experiments. With this motivation, this study focused on the cooling performance of MNFs including the experimental and numerical approaches. Until now, research on the cooling effect of MNF has focused mainly on heat propagation without any real magnetic system, in which the magnetic force plays a key role in driving fluidic flow. This flow driven by the magnetic force density was related to the magnetoconvection effect. To analyze this effect quantitatively, a coupled analysis technique should be developed using the magnetic-thermal-fluidic equations. To validate the cooling performance of MNFs numerically, the numerical results were verified by a comparison with those from the experimental tests in the air, transformer oil, and MNF. After confirming the numerical setup, some experiments were conducted with a vertical solenoid coil immersed in a MNF with different volume fractions of magnetic nanoparticles. The temperature at the inside part of the coil decreased dramatically by approximately 5 $^{\circ}$ C in the 7 vol. % MNF compared to the transformer oil. These temperatures were also predicted well using the proposed numerical setup.

Calibration of a Quasi-Adiabatic Magneto-Thermal Calorimeter Used to Characterize Magnetic Nanoparticle Heating

To assess and validate temperature measurement and data analysis techniques for a quasi-adiabatic calorimeter used to measure amplitude-dependent loss power of magnetic nanoparticles exposed to an alternating magnetic field (AMF) at radiofrequencies (160 ± 5 kHz). The data collected and methods developed were used to measure the specific loss power (SLP) for two magnetic iron oxide nanoparticles (IONPs) suspensions, developed for magnetic nanoparticle hyperthermia. Calibration was performed by comparing measured against calculated values of specific absorption rate (SAR) of a copper wire subjected to AMF. Rate of temperature rise from induced eddy currents was measured (n = 4) for a copper wire of radius 0.99 mm and length of 3.38 mm in an AMF at amplitudes (H) of 16, 20, 24, and 28 kA/m. The AMF was generated by applying an alternating current using an 80-kW induction power supply to a capacitance network containing a 13.5-cm vertical solenoid that held the calorimeter. Samples were taped to an optical fiber temperature probe and inserted into a standard (polystyrene, 5 ml) test tube which was suspended in the calorimeter. The sample was subjected to the AMF for 30 s or until the temperature of the sample, increased by 30 °C, recorded at 0.3-s intervals. The SAR of the sample was normalized by H2f1/2, averaged, and compared to theoretical values. Iron (Fe) normalized SLPs of two IONPs (JHU-MION and bionized-nanoferrite (BNF) particles (Micromod Partikeltechnologie, GmbH)) in aqueous suspension were measured in the same setup. We report experimental SAR values for the copper of 2.4 ± 0.1, 4.3 ± 0.2, 6.2 ± 0.1, and 8.5 ± 0.1 W/g compared to theoretical values 3.1 ± 0.1, 4.5 ± 0.2, 6.5 ± 0.1, and 9.2 ± 0.2 W/g at AMF amplitudes of 16 ± 0.1, 20 ± 0.2, 24 ± 0.1, and 28 ± 0.1 kA/m, respectively. Normalized experimental data followed a linear trend approximately parallel to theoretical values with an R2-value of 0.99. The measured SLPs of the JHU particles are higher than BNF particles within the tested AMF amplitude range of 15 kA/m to 45 kA/m. We demonstrated that copper can be used to calibrate magneto-thermal calorimetric systems used for SLP measurements of magnetic nanoparticles for a field range of 15–28 kA/m at 160 ± 5 kHz. We also note that the electrical conductivity, diameter of copper sample and accuracy, and response time of thermometry constrain calibration to lower amplitudes, highlighting the need for development of standard reference materials for such applications.

Wide Angle Polarization Analysis with Neutron Spin Filters

Abstract We report substantial improvements in a compact wide angle neutron spin filter system that was recently employed on the Multi- Axis Crystal Spectrometer at the Center for Neutron Research at the U.S. National Institute of Standards and Technology. The apparatus consists of a cylindrical 3He polarizer cell and wide-angle 3He analyzer cells, a vertical solenoid to provide a uniform magnetic field, and a shielded radio-frequency solenoid for the polarizer cell. Nuclear magnetic resonance is employed to reverse the polarization in the polarizer cell and monitor the 3He polarization in all cells. The first experiment using this apparatus was carried out with cylindrical analyzer cells with limited angular coverage due to low polarizations in fused quartz cells. We present results for aluminosilicate glass analyzer cells that cover 110 ∘ and have long relaxation times (100 h to 400 h). Using two 100 W diode bars spectrally narrowed with chirped volume Bragg gratings, we have obtained 65% - 80% 3He polarization in these cells. The 3He polarization has been measured by neutron transmission and electron paramagnetic resonance. Additional progress includes an improved holding field solenoid and decreased spin-flip losses.

A compact and fast nano-stylus profiling head for optical instruments

The current study developed a compact and high-speed stylus-profiling head with overall dimensions of 34.3 × 32.5 × 33.7 mm3. A simple linear flexure leaf spring was used as a precision guide method for the profiling head along a vertical axis and for the assembly of an infrared light-emitting diode. A position-sensitive photo-diode was used for as a simple sensing method. The static and dynamic forces, which can be controlled electronically using a vertical solenoid, were in the range of 10−2 N to 10−5 N. Displacement was in the range of 80 nm to 87.2 μm, making it adequate for the precise surface measurements of hard materials. The sensor resolution was less than 10 nm. The designed profiling head had a moving mass of 1 mg and speed within 100 Hz.

Switched-inductor VCO based on tapped vertical solenoid inductors

A new switched-inductor voltage controlled oscillator (VCO) scheme based on tapped vertical solenoid inductors is presented. With tapping ports, various effective inductances are selected by switches for multi-band operation. As a proof of concept, two VCOs, with one and two tapping ports separately, are implemented in a 0.18 µm 1P6M standard CMOS. Because of the vertical structure of the inductors, the new scheme consumes much less area than the conventional switch-inductor VCOs. The measured frequency bands of the VCOs are located between 1.96 and 3.49 GHz, and the measured phase noise at 1 MHz offset is between −115.4 and −118.5 dBc/Hz across all bands under power consumption of 14.4 mW (8 mA, 1.8 V).

An on-chip vertical solenoid inductor design for multigigahertz CMOS RFIC

This paper presents a compact and high-quality on-chip vertical solenoid inductor design. By taking advantage of an ever increasing number of metal layers in the modern CMOS process, the proposed structure can continuously reduce the inductor area and increase the quality factor (QF) and self-resonant frequency (SRF). Experimental results show that, compared to the 4.1-nH planar spiral inductor using a six-metal layer process, the 4.8-nH vertical solenoid inductor approximately gives a 20% increase in the maximum QF and 50% increase in the SRF, but only occupies 20% of the area. A detailed design methodology for the optimal inductor geometry will be explained. Using a standard six-metal layer CMOS process, simulation results indicate that an inductor with a 40-/spl mu/m radius and 10-/spl mu/m metal width should be used for an amplifier load, which requires 30% frequency tuning range at 5.2 GHz. An additional 7.8-dB signal gain can be obtained if the frequency tuning range requirement is reduced by one-half. Furthermore, to help the designers' decision, contour plots will be presented as a guideline. Lastly, several design guidelines will be presented.

XXXI.—On Two Relations in Magnetism

The object of this paper is to derive two relations in magnetism. In substance they are not new, but in method of statement they are, and the derivation presented here is shorter and simpler than other methods.Consider a ferro-magnetic wire hanging vertically inside a vertical solenoid with heating jacket, a pan being attached to the lower end of the wire for holding weights. Then, if hysteresis be neglected, the state of the wire may be regarded at any time as a function of the three independent variables T, F, and H,—temperature, stretching force, and magnetic field intensity.

Magnetostriction

IN your issue of March 24, 1904, Mr. Nagaoka gives an account of a lecture experiment on magnetostriction; a few weeks later Prof. W. S. Franklin describes an experiment of the same kind. Both experimenters use a vertical solenoid, along the axis of which is fixed at its upper extremity an iron wire. When a current is sent through wire and solenoid, the wire is twisted. The explanation given is that the wire is magnetised helically, the expansion along the lines of magnetisation resulting in a twist of the free lower extremity.