Printed Circuit Board Coil Research Articles

Contactless and continuous sodium concentration monitoring during continuous renal replacement therapy

A frequent complication of critically ill patients in intensive care units suffering from acute kidney injury is a severe dysnatremia requiring a continuous renal replacement therapy. For such patients, an individual dialysis treatment with an individual composition of the dialysate to limit the rate of serum sodium normalization has a positive effect on patients’ recovery. However, a precise control of the serum sodium concentration change requires continuous sodium monitoring. Drawing blood samples and analyzing such samples with a blood gas analyzer gives the serum sodium concentration with an absolute accuracy of about 2 mmol/L and a precision of 0.6 mmol/L. Nevertheless, blood gas analyzers do not allow for continuous serum sodium monitoring. Therefore, we present a new sensing concept based on a differential transformer consisting of printed circuit board coils for contactless and noninvasive monitoring of the serum sodium concentration during continuous renal replacement therapy to enable an individual sodium management. This sensing concept covers a linear operating range from 100 mmol/L to 170 mmol/L, comparable to commercially available blood gas analyzers. In a preclinical investigation using reconfigured human packed red blood cells as test medium, we could continuously measure the serum sodium concentration with an absolute accuracy of 4 mmol/L compared to the reference and a precision of 0.3 mmol/L. Moreover, we have established an analytical expression to optimize the differential transformer coils, resulting in a high sensitivity of 192 mV/mol/L.

Structure and modelling of four‐layer screen‐returned PCB Rogowski coil with very few turns for high‐bandwidth SiC current measurement

Accurate measurement of current through a silicon carbide (SiC) device is especially challenging, because of its fast switching speed. Its accompanied current sensor must hence have a high-bandwidth and a high-noise immunity. It must also not interfere with operation of the device. Due to these, the printed-circuit-board (PCB) Rogowski current sensor is particularly suitable, but normally requires many layers. With only four layers, the existing Rogowski coils are not yet capable of shielding ambient voltage and magnetic noises simultaneously. Moreover, their computed and measured self-inductances are usually very different with errors as high as 45% reported in the literature. To resolve these issues, an alternative four-layer screen-returned PCB coil has been presented. The described coil uses very few turns to preserve its high bandwidth at the expense of even tougher determination of its self-inductance. An alternative piecewise modelling method has therefore been proposed for finding its self-inductance, needed for designing its theoretical bandwidth. These, together with a non-inverting integrator, permit current through an SiC device to be measured accurately, as demonstrated experimentally.

A Novel $In-Situ$ Radiation Damage Diagnostic System for Undulators

Radiation damage has been a known problem at many synchrotron radiations and free-electron lasers facilities, especially those that use hybrid or pure permanent magnet undulators to produce high brightness light. Field strength loss due to demagnetization makes it necessary to remove the insertion device from the tunnel for inspection and repair, which brings several inconveniences. We aimed to develop an in situ radiation damage detection system for undulators capable of diagnosing relative field changes of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> (100 ppm) or smaller. The system measures the flux change in a flexible printed circuit board coil attached to the undulator magnet array by periodically measuring the integral flux change during the opening and closing of the undulator gap. If the magnet block damage occurs, the signal from the coil will decrease proportionally to the damage. First tests performed on variable gap hybrid undulators for the Linac Coherent Light Source II (LCLS-II) at SLAC National Accelerator Laboratory showed that the system is capable of measuring flux changes with a relative precision of approximately 0.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> over several days. Relative field changes smaller than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> were detected in short-term measurements. The novel system that we propose here opens the possibility of detecting radiation damage in undulators during operation.

Smartwatch Strap Wireless Power Transfer System With Flexible PCB Coil and Shielding Material

In this paper, we designed and demonstrated a smartwatch strap wireless charging system for the first time. First, we designed a flexible printed circuit board (PCB) coil, shielding material, and receiver (Rx) circuit in a watchstrap. In the design process, we proposed a model for the flexible PCB coil with a bending radius of 40 mm and shielding materials. We used a flexible PCB coil that has 215 μ m thickness with dimensions of 54.5 × 16 mm. In addition, ferrite core and sheet are applied on the transmitter (Tx) and Rx coils. We verified the proposed model through a three-dimensional (3-D) electromagnetic (EM) simulation and measurement in the frequency and time domains. The proposed flexible PCB coil inductance modeling results showed 7.5% and 3.4% errors when compared to the 3-D EM simulation and measurement results, respectively. Furthermore, we demonstrated the smartwatch strap wireless charging system using an LG Watch Urbane. A resonance frequency of 100 kHz with the series–series tuning topology is used in accordance with the Qi specifications. Finally, we achieved 30% dc–dc power transfer efficiency and exposed magnetic field of 270 mG, 1 cm away from the system through measurements.

Evaluation of Specific Absorption Rate in Three-Layered Tissue Model at 13.56 MHz and 40.68 MHz for Inductively Powered Biomedical Implants

This paper presents an optimized 3-coil inductive wireless power transfer (WPT) system at 13.56 MHz and 40.68 MHz to show and compare the specific absorption rate (SAR) effects on human tissue. This work also substantiates the effects of perfect alignment, lateral and/or angular misalignments on the power transfer efficiency (PTE) of the proposed WPT system. Additionally, the impacts of different tissue composition, input power and coil shape on the SAR are analyzed. The distance between the external and implantable coils is 10 mm. The results have been verified through simulations and measurements. The simulated results show that the SAR of the system at 40.68 MHz had crossed the limit designated by the Federal Communications Commission and hence, it is unsafe and causes tissue damage. Measurement results of the system in air medium show that the optimized printed circuit board coils at 13.56 MHz achieved a PTE of 41.7% whereas PTE waned to 18.2% and 15.4% at 10 mm of lateral misalignment and 60° of angular misalignment respectively. The PTE of a combination of 10 mm lateral misalignment and 60° angular misalignment is 21%. To analyze in a real-environment, a boneless pork sample with 10 mm of thickness is placed as a medium between the external and implantable coils. At perfect alignment, the PTE through pork sample is 30.8%. A RF power generator operating at 13.56 MHz provides 1 W input power to the external coil and the power delivered to load through the air and tissue mediums are 347 mW and 266 mW respectively.

Calibration technique for rotating PCB coil magnetic field sensors

A high-accuracy calibration of inductive coil sensors based on Printed Circuit Board (PCB), commonly used in rotating coil field measurements of particle accelerator magnets, is presented. The amplitude and phase of signals with and without main field suppression are compared in order to simultaneously determine both the PCB rotation radius and the transverse offset of its plane from rotation center. The accuracy of planar wire placement on the PCB boards is exploited to create loops highly precise in area which rotate at different radii. Such an area reproducibility and circuit geometry allow the suppression of the fundamental field, enabling the calibration, as well as improving signal resolution and mitigating vibration effects. Furthermore, the calibration can be performed dynamically, in-situ during measurements. Calibration accuracy is validated experimentally by referencing the PCB positions with a Coordinate Measuring Machine (CMM).

Fast Fourier Transform Based NDT Approach for Depth Detection of Hidden Defects Using HTS rf-SQUID

We present a new approach for depth detection of hidden defects based on the analysis of the frequency spectrum of the output waveform in a nondestructive testing (NDT) system. In our eddy current Superconducting quantum interference device (SQUID) based NDT system, we apply multiple frequencies to its single excitation coil in a magnetically unshielded environment. The excitation coil is a planar D-shaped printed circuit board coil, and a high-T c gradiometer YBCO rf-SQUID is used as the electromagnetic sensor in this system. An automated two-dimensional nonmagnetic scanning robot is used to test samples with intentional defects at different depths. In this approach, a diagram labeled “FFT relative changes” is assigned to each test sample. The optimum points of the FFT relative changes diagram occur at the optimum frequencies directly related to the depth of the corresponding defects. The relation between the optimum frequency and the corresponding depth in our system is obtained both experimentally and by simulation. An excellent agreement between the practical and the simulation results confirmed the accuracy of the proposed method.

High-Resolution 2D Magnetic Field Measurement of Magnetic Reconnection Using Printed-Circuit Board Coils

High-Resolution 2D Magnetic Field Measurement of Magnetic Reconnection Using Printed-Circuit Board Coils

Design and theoretical analysis of current transformer based on B-dot planar printed circuit board coil

PurposeThe purpose of this paper is to design a current transformer model based on the principle of B-dot. It can reflect the change of transmission line current and meet the requirement of automation and intelligence for current measurement in power system.Design/methodology/approachIn this paper, a new type of current transformer is designed on the principle of B-dot, which has the structure of the inverse series of planar air core coils and the form of printed circuit board (PCB). With this structure, the current transformers can induce magnetic field quite well. The finite element simulation for the current transformer with n layers structure is conducted in the Maxwell, which help to optimize the design of the current transformer.FindingsBy setting up the experimental platform, the experiment of the current transformer is carried out. The results of the test show that the measurement accuracy can satisfy the requirement of measurement. Besides, the new current transformer has good transient characteristics and can meet the needs of the development of smart grid.Originality valueThe new type of current transformer is based on the principle of B-dot, which is designed with a new type of non-contact PCB hollow coil current transformer. It has no iron core, no ferromagnetic effect and the phenomenon of ferromagnetic resonance. It has great progress in its insulation performance, volume and bandwidth response. In addition, the planar hollow coil of the inverse series structure can make the structure more accurate.

Measurement of the ripple of magnet power supply and its effect to the beam energy

This study is aimed at measuring the ripple of magnetic power supply of BEPCII and checking its effect to beam energy. A sensor made of printed circuit board coils is designed and manufactured. The sensor was inserted into a good area region of the magnetic field with the surface perpendicular to the field force lines. The change of the magnetic field would be detected according to Faraday’s law. The experiment result indicates that the time-dependent ripple of the magnetic field is in the magnitude of ppm. Such a small effect of the time-dependent ripplecan be negligibleto beam energy.

Influencing Factors of Inductance for 3D Micro-PCB Rectangular Coil

The main constraint that restricts wireless charging technology successfully applied in miniature medical electronic equipment is that the volume of the transmission coil is difficult to reduce. The printed circuit board (PCB) coil can take advantage of multi-layer wiring space to achieve the coil stack, achieving the purpose of increasing the relative magnetic flux, so that it could replace the traditional spiral coil to become the medium of wireless power transmission in the mini-medical electronic device. In this paper, we analyzed several electrical parameters that could affect the 3D PCB rectangular coil inductance value based on the 3D PCB rectangular coil inductance computing method. Then we sort these influencing factors so that these results can help designers to design the 3D PCB coil. The conclusions are as follows: (1) number of layers, total number of turns have positive correlation with the self-inductance; metal width, substrate thickness, the pitch between adjacent turns have negative correlation with the self-inductance. (2) The sorting of influencing factors of the inductance is as follows: total number of turns[Formula: see text]number of layers, the pitch between adjacent turns[Formula: see text]substrate thickness[Formula: see text]metal width.

Effect of Layer Spacing and Line Width of PCB Coil on Resonant Frequency

With the development of electronic science and technology, people have entered the information society, a variety of portable electronic products enter people’s lives. A large number of miniature human implantable medical devices applied to clinical fields. The traditional human implantable medical device power supply is implanted battery, its biggest drawback is the treatment problem after the battery power consumption. Whether it is taken to replace the new battery, or deep into the body, there is a huge risk. Therefore, the portable external wireless charging, it becomes the best choice for human implantable medical devices. Because some of the implanted device volume is very small, they can't accommodate bulky solenoid coil, which seriously restrict the application of wireless charging technology in implantable medical devices. Printed circuit board (PCB) coil has the advantages of high wiring density, small volume, light weight, beneficial to the miniaturization of electronic equipment, they can replace traditional solenoid coil, and applied to the wireless charging technology. In this paper, HFSS software is used to simulate, a large number of simulation experiments are carried out on the PCB with 2 layers coils. At the same time, the electrical parameters such as layer spacing, line width and resonant frequency are analyzed. Finally, the conclusion is: in the case of fixed layer spacing, with the increasing of the line width, the resonance frequency is gradually reduced; but the resonance frequency is reduced to a certain extent, it is not changed. When line width is fixed, with the growing layer spacing, the resonance frequency value is constantly increasing, the resonant frequency of the growth is also more and more slow.

6.78MHz, 거리 60cm, 50W급 무선 전력 전송 시스템용 High Quality Factor PCB 코일 개발

6.78MHz, 거리 60cm, 50W급 무선 전력 전송 시스템용 High Quality Factor PCB 코일 개발

Design and experimental demonstration of electromagnetic actuation utilized on micrograting accelerometers.

This paper presents the design, analysis, and experimental demonstration of electromagnetic actuation utilized on micrograting accelerometers. It mainly consists of a permanent magnet and a driving coil made of three planar printed circuit board coils. A silicon movable platform and the permanent magnet with an axial magnetization of 750×103 A/m form the proof mass. The eight cantilever beams and the movable platform are made by means of the etching process, and the aluminum micrograting is fabricated by the lift-off process. Experimental data show that the electromagnetic force can reach 1.41 mN when the driving voltage is about 2.96 V. The linear operating region of the accelerometer is [-1 g,1 g] under a driving voltage of -2.8 to 2.96 V. A mean sensitivity of 2.82 V/g is obtained by three repeated feedback experiments. In addition, a linear operating region of [-2.2 g,2.2 g] is calculated when the driving voltage is [-7 V,7 V]. There is a linear relation between the driving voltage and the input acceleration.

A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines

The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices.

Comparison of an Electromagnetic Energy Harvester Performance using Wound Coil Wire and PCB Coil

This paper presents the performance of two types of electromagnetic energy harvester, one using manually wound coil wire (EH-EC) and the other one using printed circuit board (PCB) coil (EH-EP). The objective of the study is to measure the corresponding output voltage and power by varying the number of coils and the position of the magnet. The experiment was conducted at a fix 50 Hz of frequency and at 0.25g of acceleration. The EH-EP was found to be more effective than the 350 turns of the wound coil wire, with maximum power of 26 μW. Overall, the performance of the EH-EC showed better result with maximum power of 125 μW for 1050 turns when compared to the EH-EP.

Design and modeling of PCB coils for inductive power charging

This article presents a modeling and parametric investigation of printed circuit board (PCB) coils used in inductive power charging systems by using intensive full-wave electromagnetic simulations. Low frequencies applications (below 1 MHz) are targeted. The proposed modeling approach and design methodology are validated for wireless power transfer systems including transmitting (Tx) and receiving (Rx) coils. The impact of ferrite materials used for shielding and efficiency improvement is also analyzed. Optimized PCB coils allowing a theoretical efficiency of 88.7% at 100 kHz and 98.5% at 1 MHz confirms that PCB coils are appropriate for wireless power transfer at such frequencies.

PCB형 코일을 이용한 비대칭 광픽업 액추에이터의 성능분석

'Coil' occupies very much important position in delivering driving force of optical pick-up actuators. Up to now the main stream has been a winding coil type actuator, but actuators using FP-Coil(fine pattern coil) have been considered for the more compacted and simple manufacturing process and have variously spreaded the application fields by product. We have tried to design actuators using PCB-Coil(printed circuit board coil) which has benefits in terms of price and manufacturing process. Especially this research has two main things to reduce the vibration of sub-resonance and to assure the DC sensitivity among the performances of asymmetric optical pick-up actuator with PCB-Coil.