Improving the quality factor of an RF spiral inductor with non-uniform metal width and non-uniform coil spacing

An improved inductor layout with non-uniform metal width and non-uniform spacing is proposed to increase the quality factor(Q factor).For this inductor layout,from outer coil to inner coil,the metal width is reduced by an arithmetic-progression step,while the metal spacing is increased by a geometric-progression step. An improved layout with variable width and changed spacing is of benefit to the Q factor of RF spiral inductor improvement(approximately 42.86%),mainly due to the suppression of eddy-current loss by weakening the current crowding effect in the center of the spiral inductor.In order to increase the Q factor further,for the novel inductor, a patterned ground shield is used with optimized layout together.The results indicate that,in the range of 0.5 to 16 GHz,the Q factor of the novel inductor is at an optimum,which improves by 67%more than conventional inductors with uniform geometry dimensions(equal width and equal spacing),is enhanced by nearly 23%more than a PGS inductor with uniform geometry dimensions,and improves by almost 20%more than an inductor with an improved layout.     

基于C8051单片机的金属探测器系统设计

为提升和完善金属探测器的性能,并且降低其成本,设计了一种基于单片机C8051F350单片机的金属探测的方案。通过采用平衡式线圈作为接收线圈来感应通电线圈周围磁场的变化,并将磁场的变化转化为电压的变化,经放大器AD620进行放大,在单片机内进行MD转换,并将测得的电压与预设的基准电压相比较来确定是否检测到了金属。本设计采用软硬件结合的方法消除干扰,提高探测器的性能,确保系统的精确性。     

非均匀金属线宽和线间距射频螺旋电感品质因子的改善

为了提高品质因子Q,本文提出了一种非均匀金属条宽和非均匀条间距的改进电感结构。从外圈到里圈,改进的电感金属线宽按等差数列逐渐减小,金属间距按等比数列增加。因为该渐变结构有效减弱了线圈中心电流拥挤导致的涡流效应,所以改进结构电感的Q因子大幅度提高（幅值高达42.86%）。为了进一步增大Q因子,新型电感同时采用图形化接地保护结构（PGS）与渐变结构。结果显示,在0.5GHz到16GHz的射频频段内,结合两种技术的新型电感的品质因子Q最优,与固定金属线宽和间距的传统电感相比,Q提高了67%;与仅采纳PGS结构的电感相比,Q提高了23%;与仅采用渐变金属结构的电感相比,Q提高了20%。     

Sensitivity maps for metal detector design

Eddy-current or permeability-contrast based metal detectors may be characterized by static sensitivity maps, a new graphic representation that maps detector response to a standardized infinitesimal object in a static field. A sphere is shown to be a suitable standard object because its behavior describes, to within multiplicative constants, objects of arbitrary conductivity and permeability. Static sensitivity maps take full account of both the excitation and detection coil shapes. They are compact, easy to understand, closely related to industrial testing procedures, and likely to prove a useful design tool. Their usefulness is illustrated by examples based on a metal detector for which published data exist     

Investigation on the layout parameters of on-chip inductor

A comprehensive discussion on the layout parameters of spiral inductor is addressed in this paper. By keeping the identical DC resistance, the variations of metal width, coil number, and metal spacing influence the RF resistance are investigated completely. Then the mechanism of induced eddy current is described to explain the influence in the design of layout parameters. Finally, the experimental result of special layout (i.e. taper inductor) is demonstrated the improved Q characteristics.     

Analytical optimization of high-performance and high-yield spiral inductor in integrated passive device technology

The analytical optimization of several spiral inductors with different inner diameters, line widths, coil spacing, turn numbers, ring shapes, metal thicknesses, and substrates was performed by the measurement-derived inductance and Q-factor. Through the analytical optimization, a thick electroplated Cu/Au metal process and an additional sputter-etching strategy on a 200 μm finished SI-GaAs substrate with the suitable layout parameters have been proposed in order to obtain the higher performance and yield for the spiral inductors. The proposed physical layouts and fabrication parameters are an optimal solution for manufacturing spiral inductors in the integrated passive device (IPD) process that require high performance, stringent size, and volumetric efficiency.     

一种基于光差拍技术的新型频率合成器的研究

提出了一种基于光差拍技术频率合成器的设计方案,频率合成器可以实现DC～×10^2GHz频率范围的梳状谱信号输出。利用10GHz光电探测器（PD）对一腔长为27m的环形腔掺铒光纤激光器输出的多纵模激光进行差拍,得到频率间隔为7．63MHz的梳状信号。受PD响应速率的影响,梳状谱信号的频率范围为DC～10GHz。在此基础上...     

Sensitivity of metal detectors to spheroidal targets

The sensitivity of magnetic metal detectors to prolate or oblate spheroidal targets depends both on the semiaxis ratio and on the orientation of the spheroid polar axis relative to the local magnetic field. A spherical target produces null response only if the generator and detector coil magnetic fields are orthogonal, but the spheroid possesses a null direction for a large range of magnetic field orientations. A spheroid can therefore be made undetectable by rotating it into a particular orientation. The existence of such blind-position angles is investigated theoretically in detail and families of curves are given to illustrate them in a particular case     

System optimization for improved accuracy in transcutaneous signal and power transmission

A stable transcutaneous transmission of power and signal via two coupled coils with minimized dependence on the relative spacing of external and implanted coil is possible by employing "critical coupling" between implanted and external circuits. Optimizing coil geometries and preventing the RF output amplifier from saturating is necessary to approximately maintain critical coupling despite placement tolerances within a reasonable range. Based on these considerations a transcutaneous signal transmission system for an auditory prosthesis has been designed. This transmission system can also be used for several other stimulation purposes needing accurate control of stimulation parameters.     

A silicon homojunction infrared detector having an active metalfilm on an n++ layer

A silicon n⁺⁺pn homojunction infrared detector, in which a degenerate n⁺⁺ layer is backed by a metal film forming an ohmic contact, has been proposed and studied. The metal film is a photoelectric conversion region along with the n⁺⁺ layer. Although, for an n⁺⁺pn detector without the metal film, very poor rectifying properties are observed when the n⁺⁺ layer thickness is extremely reduced, the new detector, employing a thin PtSi film as the metal film, shows normal diode I-V characteristics, since the PtSi film provides increased surface conductivity. The new detector has achieved an increase in operatable temperature, or an extension of cutoff wavelength, and operated with cutoff wavelengths of 11.9 μm, 18.7 μm and about 30 μm at 70 K, 50 K, and 30 K, respectively, because the saturation current density for the new detector has been reduced to about one tenth that for the previously reported n⁺⁺pn detector. The responsivity for the new detector has increased to 1.1-3.8 times as large as that for the previously reported n⁺⁺pn detector, when both detectors have the same cutoff wavelength     

Two-dimensional numerical computation of the structure-dependent spectral response in a 4H-SiC metal-semiconductor-metal ultraviolet photodetector with consideration of reflection and absorption on contact electrodes

A two-dimensional model of a 4H-SiC metal-semiconductor-metal(MSM) ultraviolet photodetector has been established using a self-consistent numerical calculation method.The structure-dependent spectral response of a 4H-SiC MSM detector is calculated by solving Poisson’s equation,the current continuity equation and the current density equation.The calculated results are verified with experimental data.With consideration of the reflection and absorption on the metal contacts,a detailed study involving various electrode heights(H),spacings (S) and widths(W) reveals conclusive results in device design.The mechanisms responsible for variations of responsivity with those parameters are analyzed.The findings show that responsivity is inversely proportional to electrode height and is enhanced with an increase of electrode spacing and width.In addition,the ultraviolet (UV)-to-visible rejection ratio is > 103.By optimizing the device structure at 10 V bias,a responsivity as high as 180.056 mA/W,a comparable quantum efficiency of 77.93%and a maximum UV-to-visible rejection ratio of 1875 are achieved with a detector size of H = 50 nm,S =9μm and W = 3μm.     

Near‐Infrared Light Propagation in an Adult Head Model with Refractive Index Mismatch

We investigate near‐infrared light (NIR) propagation in a model of an adult head using an extensive Monte Carlo (MC) simulation. The adult head model is a four‐layered slab which consists of a surface layer, a cerebrospinal fluid layer, a gray‐matter layer, and a white‐matter layer. We study the effects of a refractive index mismatch on the model, calculating the intensity of detected light, mean flight time, and partial mean flight time of each layer for various refractive indices of the cerebrospinal fluid layer as functions of source‐detector spacing. The Monte Carlo simulation shows that the refractive index mismatch presents very rich results including rapidly decaying intensity of detected light and a peak and cross‐over in the partial mean flight time with source‐detector spacing. We also investigate spatial sensitivity profiles at various source‐detector spacings, discussing the index mismatch effect on the model.     

Passband Control of Surface Magnetostatic Waves by Spacing a Metal Plate Apart from the Ferrite Surface

The effect of a metal plate on the propagation characteristics of surface magnetostatic waves (SMW) propagating perpendicular to an external dc magnetic field was studied by varying the spacing of the metal plate from the ferrite surface. Continuous passband control is obtained by changing the spacing from zero to infinity and the existence of a partial stopband for the interchange of the input and output ports is also obtained in addition to the disappearance of nonreciprocal propagation for a finite spacing of the metal plate.     

Development of emulator for walk-through metal detectors

Because of anecdotal reports that magnetic fields from walk-through metal detectors may interfere with the operation of personal medical devices, interest has grown in the development of emulators that can simulate the magnetic fields produced by these metal detectors. This paper describes a system that can produce linearly polarized magnetic fields that have temporal characteristics such as those generated by some walk-through metal detectors. Because the electronic components are "off-the-shelf" devices and the coil can be readily fabricated, the system could be used by manufacturers of medical devices to conduct their own electromagnetic interference tests     

Fibre-optic spectrophone

The first operation of a fibre-optic spectrophone is reported. A 2.54 cm diameter coil of single-mode fibre was fused into one arm of an all-fibre Mach-Zehnder interferometer. The device operated as a highly sensitive optoacoustic detector.     

Microwave Probes for Electric Fields Near Metal Surfaces

An experimental study was made to isolate the types of probe errors made in measuring electrical boundary conditions and nearfield waves over the surfaces of metal diffracting objects and antennas. Because their patterns could be calculated for comparison with measurements, thin metal disks were employed ranging in diameters from 0.1 to 10 wavelengths. The microwave wavelengths ranged from 2 to 80 cm and the probe sizes ranged from 0.50 to 0.01 wavelength long. The probes consisted of wire dipoles with the microwave circuits confined to the detector capsule at the centers of the dipoles. Three types of probe errors were studied: 1) multiple reradiation between probe and surface of object when the axis of the probe is parallel to the surface, 2) bringing the tip of the probe closer than a hundredth of a wavelength from the surface of the object when the fields between the tip and the surface are shaped like electrostatic fields and found to be grossly affected by changes in the spacing, and 3) lengths of probes large compared to the radius of curvature of the lines of force, a limiting case in the measurement of fields near the edges of metal sheets.     

红外探测器组件激光封口技术研究

高气密激光封口技术是一种可用于金属管壳的封装技术。它能在高真空环境中 使开有小孔的管壳器件实现封口密封,从而使排气工艺与封口工艺同步完成。针对微型管壳的结构和材料 特点,研究了激光焊接设备的电流和脉宽与焊接能量的关系以及电流、脉宽和离焦量对封口质量的影响,得到了柯伐 材料的激光封口参数,并将这些工艺参数应用到了红外探测器金属管壳的激光焊接中。测试结果表明,其漏率均优于1×10-10Torr.l/S。     

Reordering Schemes for Multiple-Rotation Fan-Beam CT Scanner

The number of detectors in a fan-beam CT scanner can be substantially decreased if a multiple-rotation data collection mode is used to provide appropriate spatial resolution. The efficiency of multiple-rotation schemes using a detector offset combined with angular shift of the detectors in each cycle for projection space filling is examined. It is shown that in reordering into parallel projections, angular interpolation can be avoided if an appropriate angular offset of the source with respect to the axis of a fan can be made in each cycle. To achieve even spacing of rays at the ends of the reordered parallel projections, the shifted positions of each detector must be symmetrical with respect to the position of the detector in the original symmetric fan. Results of the computer simulation are presented.     

Direct fourier reconstruction in fan-beam tomography

We consider the problem of reconstructing tomographic imagery from fan-beam projections using the direct Fourier method (DFM). Previous DFM reconstructions from parallel-beam projections produced images of quality comparable to that of filtered convolution back-projection. Moreover, the number of operations using DFM in the parallel-beam case is proportional to N2 log N versus N3 for back projection [3]. The fan-beam case is more complicated because additional interpolation of the nonuniformly spaced rebinned data is required. We derive bounds on the detector spacing in fan-beam CT that enable direct Fourier reconstruction and describe the full algorithm necessary for processing the fan-beam data. The feasibility of the method is demonstrated with an example. A key result of this paper is that high-quality imagery can be reconstructed from fan-beam data using the DFM in 0 (N2 log N) operations.     

Introduction to the special issue on IEEE NEWCAS 2017

A contactless detector is presented for evaluating hand tremors caused by exercise-induced fatigue and early Parkinson’s disease. The device consists of a spiral coil, a microcontroller, and an inductive sensor circuitry. Theory shows that the resonant frequency of the circuitry increases when the distance between the hand and the spiral coil decreases, thus small variations of distance from tremor can be detected from the changes of resonant frequencies. A mechanical hand was built for experiments to simulate human hand tremors with repeatability at a fixed frequency. The magnitudes and frequencies of the tremors in the mechanical hand were quantitatively identified using the inductive sensor. Hence, feasibility and accuracy of the contactless hand tremor detector were determined. A triaxial accelerometer was used for comparison. By comparing spectral distributions and magnitudes of the tremors, the inductive sensor performed better than the accelerometer. The detector was applied to evaluate actual hand tremors of three subjects who had undergone exercise to induce tremors. The tremor waveform amplitudes of the subjects were quantitatively analyzed by the standard deviations method. The increased signal energies of exercise-induced tremor within 8–12 Hz were confirmed. Then, a subject with early Parkinson’s disease was evaluated by the proposed hand tremor detector. The tremor magnitudes and frequencies of the patient hand were quantitatively identified within in 4–7 Hz. Therefore, the new contactless hand tremor detector can be developed as a clinical instrument for monitoring the fatigue symptoms of post-exercise and diagnosing the early Parkinson’s disease.