Small Split-Ring Resonators as Efficient Antennas for Remote LoRa IOT Systems—A Path to Reduce Physical Interference

While wireless IOT modules can be made extremely compact, antennas typically protrude from the module, providing the potential to catch near moving/rotating equipment or transfer loads to the PCB through end forces, which can lead to failures. This work explores the use of split-ring resonator (SRR) designs to achieve a planar antenna with a maximum dimension less than a monopole working at the same frequency. The very narrow bandwidth of the SRR required detailed physical models to create printed circuit board (PCB)-based antenna designs that could be used at LoRa frequencies of 433 MHz and 915 MHz. Uncertainty analysis allowed for the impact of geometrical and physical tolerances on the resonant frequency to be evaluated. Nearfield and farfield measurements were performed allowing for the resonant frequency, directionality, and range of the antenna to be evaluated. An unbalanced SMA port was added to the SRR design to allow for the use of a network vector analyser to determine the input impedance of various designs. The optimum design achieved an input resistance of 44 Ω at a resonant frequency of 919 MHz, close to the target values (50 Ω at 915 MHz). Field measurements of the received signal strength from a planar antenna design indicated a gain of 5 dB over a conventional quarter-wave monopole antenna, in a footprint that was 40% smaller than the monopole.

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A 4 × 4 Array of Complementary Split-Ring Resonators for Label-Free Dielectric Spectroscopy

Chemosensors ◽

10.3390/chemosensors9120348 ◽

2021 ◽

Vol 9 (12) ◽

pp. 348

Author(s):

Matko Martinic ◽

Tomislav Markovic ◽

Adrijan Baric ◽

Bart Nauwelaers

Keyword(s):

Dielectric Spectroscopy ◽

Large Scale ◽

Printed Circuit Board ◽

Sensor Arrays ◽

Split Ring Resonator ◽

Circuit Board ◽

Ring Resonators ◽

Label Free ◽

Split Ring ◽

Complementary Split Ring Resonator

In this study, complementary split-ring resonator (CSRR) metamaterial structures are proposed for label-free dielectric spectroscopy of liquids in microplates. This novel combination of an array of sensors and microplates is readily scalable and thus offers a great potential for non-invasive, rapid, and label-free dielectric spectroscopy of liquids in large microplate arrays. The proposed array of sensors on a printed circuit board consists of a microstrip line coupled to four CSRRs in cascade with resonant frequencies ranging from 7 to 10 GHz, spaced around 1 GHz. The microwells were manufactured and bonded to the CSRR using polydimethylsiloxane, whose resonant frequency is dependent on a complex relative permittivity of the liquid loaded in the microwell. The individual microstrip lines with CSRRs were interconnected to the measurement equipment using two electronically controllable microwave switches, which enables microwave measurements of the 4 × 4 CSRR array using only a two-port measurement system. The 4 × 4 microwell sensor arrays were calibrated and evaluated using water-ethanol mixtures with different ethanol concentrations. The proposed measurement setup offers comparable results to ones obtained using a dielectric probe, confirming the potential of the planar sensor array for large-scale microplate experiments.

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Passive Split Ring Resonator for Continuous Physiological Sensing Through Conductivity Measurements

Volume 10: Micro- and Nano-Systems Engineering and Packaging ◽

10.1115/imece2013-66744 ◽

2013 ◽

Author(s):

Evan Baker ◽

Noah Shaw ◽

Chen Wang ◽

Hao Zhang ◽

Cheng Sun

Keyword(s):

Resonant Frequency ◽

Printed Circuit Board ◽

Ring Resonator ◽

Fdtd Method ◽

Split Ring Resonator ◽

Circuit Board ◽

Q Factor ◽

Split Ring ◽

Resonator Structure ◽

Radio Band

The Split Ring Resonator (SRR) has been developed and explored for a number of sensing technologies and devices. A SRR can be equivalently regarded as an LC circuit; changes in the dielectric environment will change the equivalent capacitance of the resonator, resulting in a shift of the resonant frequency as well as the quality factor (Q-factor).This makes the device a promising application for continuous personal health monitoring throughout the day. In this work, we are developing a passive radio frequency sensor based on ring resonator designs. The targeted frequency band is within 2.4–2.5GHz ISM (Industrial-Scientific-Medical radio band) and is available for medical devices. The resonator structure is first simulated using Finite Difference Time Domain (FDTD) method by CST Microwave Studio to determine the resonant frequency. Then for the experimental study, a microstrip transmission line with a double split ring resonator (DSRR) was fabricated on a printed circuit board (PCB) with biocompatible PVC coating on top. Tuning the thickness and material of the biocompatible coating can further improve the biocompatibility, Q-factor, and resulting sensitivity (mS) of the device. Reflection spectrum (S11) is measured using a network analyzer at 100 mW. The current design senses changes in conductivity down to 0.5 mS. By reducing coating thickness, reducing the spacing between resonators, and with more efficient resonator designs we expect to further improve this sensitivity. This sensor could be utilized by either implanted into the interstitial layer beneath the skin or embedded into a contact lens to sense tear salinity levels.

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Numerical Simulation and Experimental Measurement of a Printed Circuit Board Subjected to Drop Test

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.37 ◽

2009 ◽

Vol 419-420 ◽

pp. 37-40

Author(s):

Shiuh Chuan Her ◽

Shien Chin Lan ◽

Chun Yen Liu ◽

Bo Ren Yao

Keyword(s):

Finite Element ◽

Experimental Measurement ◽

Test Specimen ◽

Printed Circuit Board ◽

Drop Impact ◽

Simulation Technique ◽

Drop Test ◽

Circuit Board ◽

Printed Circuit ◽

The Impact

Drop test is one of the common methods for determining the reliability of electronic products under actual transportation conditions. The aim of this study is to develop a reliable drop impact simulation technique. The test specimen of a printed circuit board is clamped at two edges on a test fixture and mounted on the drop test machine platform. The drop table is raised at the height of 50mm and dropped with free fall to impinge four half-spheres of Teflon. One accelerometer is mounted on the center of the specimen to measure the impact pulse. The commercial finite element software ANSYS/LS-DYNA is applied to compute the impact acceleration and dynamic strain on the test specimen during the drop impact. The finite element results are compared to the experimental measurement of acceleration with good correlation between simulation and drop testing. With the accurate simulation technique, one is capable of predicting the impact response and characterizing the failure mode prior to real reliability test.

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High quality factor fractal inductor with complementary split-ring array inclusion

Circuit World ◽

10.1108/cw-06-2019-0052 ◽

2020 ◽

Vol 46 (3) ◽

pp. 215-219

Author(s):

Akhendra Kumar Padavala ◽

Narayana Kiran Akondi ◽

Bheema Rao Nistala

Keyword(s):

Quality Factor ◽

Circuit Design ◽

Integrated Circuit ◽

Printed Circuit Board ◽

Three Dimensional ◽

Circuit Board ◽

Integrated Circuit Design ◽

Split Ring ◽

Content Type ◽

Practical Implications

Purpose This paper aims to present an efficient method to improve quality factor of printed fractal inductors based on electromagnetic band-gap (EBG) surface. Design/methodology/approach Hilbert fractal inductor is designed and simulated using high-frequency structural simulator. To improve the quality factor, an EBG surface underneath the inductor is incorporated without any degradation in inductance value. Findings The proposed inductor and Q factor are measured based on well-known three-dimensional simulator, and the results are compared experimentally. Practical implications The proposed method was able to significantly decrease the noise with increase in the speed of radio frequency and sensor-integrated circuit design. Originality/value Fractal inductor is designed and simulated with and without EBG surfaces. The measurement of printed circuit board prototypes demonstrates that the inclusion of split-ring array as EBG surface increases the quality factor by 90 per cent over standard fractal inductor of the same dimensions with a small degradation in inductance value and is capable of operating up to 2.4 GHz frequency range.

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Implementation and Experimental Verification of Smart Junction Box for Low-Voltage Automotive Electronics in Electric Vehicles

Applied Sciences ◽

10.3390/app10072214 ◽

2020 ◽

Vol 10 (7) ◽

pp. 2214

Author(s):

Sang Wook Lee ◽

Soo-Whang Baek

Keyword(s):

Electric Vehicles ◽

Printed Circuit Board ◽

Pulse Width Modulation ◽

Low Voltage ◽

Short Circuit ◽

Circuit Board ◽

Area Network ◽

Automotive Electronics ◽

Overload Protection ◽

The Impact

In this study, we designed and implemented a smart junction box (SJB) that was optimized for supplying power to low-voltage headlights (13.5 V) in electric vehicles. The design incorporated a number of automotive semiconductor devices, and components were placed in a high-density arrangement to reduce the overall size of the final design. The heat generated by the SJB was efficiently managed to mount an Intelligent Power Switch (IPS), which was used to power the headlights onto the printed circuit board (PCB) to minimize the impact on other components. The SJB was designed to provide power to the headlights via pulse width modulation to extend their lifetime. In addition, overload protection and fail/safe functions were implemented in the software to improve the stability of the system, and a controller area network (CAN) bus was provided for communications with various components in the SJB as well as with external controllers. The performance of the SJB was validated via a load operation test to assess the short circuit and overload protection functions, and the output duty cycle was evaluated across a range of input voltages to ensure proper operation. Based on our results, the power supplied to the headlights was found to be uniform and stable.

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Research on Liberation Mechanism of the Impact Crushing Waste Printed Circuit Board

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.730 ◽

2010 ◽

Vol 113-116 ◽

pp. 730-734 ◽

Cited By ~ 3

Author(s):

Chen Long Duan ◽

Yue Min Zhao ◽

Jing Feng He ◽

Nian Xin Zhou

Keyword(s):

Printed Circuit Boards ◽

Printed Circuit Board ◽

Circuit Board ◽

Distribution Model ◽

Evaluation Indexes ◽

Printed Circuit ◽

Waste Printed Circuit Boards ◽

Waste Printed Circuit Board ◽

Impact Crushing ◽

The Impact

The reutilization of waste Printed Circuit Boards (PCB) is a focused topic in the field of environment protection and resource recycling, and the crushing is the crucial process for recycling waste PCB. A hamper impacting crusher was used to achieve metals crushing liberation from non-metals, the liberation mechanism of PCB can be explained by dispersion liberation accompanied disengaging liberation. The Rosin-Rammler distribution model of crushed PCB particle was put forward. The evaluation indexes show that Rosin-Rammler function can accurately describe size distribution of PCB particles because the convergence property R2 is 0.99694 and fitting error E is 4.80658. The selective crushing is appearance with metals concentrated in coarser fraction and non-metals in finer size during comminution processing. The impact crushing is an effective method to metals liberation of PCB particles.

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Failure Analysis of Halogen-Free Printed Circuit Board Assembly Under Board-Level Drop Test

Journal of Electronic Packaging ◽

10.1115/1.4005956 ◽

2012 ◽

Vol 134 (1) ◽

Cited By ~ 2

Author(s):

Hung-Jen Chang ◽

Chau-Jie Zhan ◽

Tao-Chih Chang ◽

Jung-Hua Chou

Keyword(s):

Printed Circuit Board ◽

Drop Test ◽

Circuit Board ◽

Printed Circuit Board Assembly ◽

Printed Circuit ◽

Plastic Ball ◽

Circuit Board Assembly ◽

Halogen Free ◽

Board Level ◽

The Impact

In this study, a lead-free dummy plastic ball grid array component with daisy-chains and Sn4.0Ag0.5Cu Pb-free solder balls was assembled on an halogen-free high density interconnection printed circuit board (PCB) by using Sn1.0Ag0.5Cu solder paste on the Cu pad surfaces of either organic solderable preservative (OSP) or electroless nickel immersion gold (ENIG). The assembly was tested for the effect of the formation extent of Ag3Sn intermetallic compound. Afterward a board-level pulse-controlled drop test was conducted on the as-reflowed assemblies according to the JESD22-B110 and JESD22-B111 standards, the impact performance of various surface finished halogen-free printed circuit board assembly was evaluated. The test results showed that most of the fractures occurred around the pad on the test board first. Then cracks propagated across the outer build-up layer. Finally, the inner copper trace was fractured due to the propagated cracks, resulting in the failure of the PCB side. Interfacial stresses numerically obtained by the transient stress responses supported the test observation as the simulated initial crack position was the same as that observed.

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Nonlinear Response of a Printed Circuit Board in Shock

ASME 2009 InterPACK Conference, Volume 2 ◽

10.1115/interpack2009-89094 ◽

2009 ◽

Cited By ~ 1

Author(s):

M. Vujosevic ◽

P. Raghavan ◽

G. Ramanathan ◽

W. Hezeltine ◽

K. Blue

Keyword(s):

Printed Circuit Board ◽

Transfer Functions ◽

Numerical Approach ◽

Circuit Board ◽

Special Importance ◽

Strain Measurements ◽

Printed Circuit ◽

Numerical Finite Element ◽

Nonlinear Deformations ◽

The Impact

This work focuses on deformation mechanisms taking place in a Printed Circuit Board (PCB) exposed to high impact shock. A combined experimental, theoretical, and numerical approach has been applied to address both the nature of the observed deformation and its modeling and test metrology implications. Experimental evidence overwhelmingly indicates that a PCB in both test and system applications undergoes nonlinear deformations. Geometric nonlinearity of board response is attributed to the elevated in-plane (membrane) stresses that develop when a drop height and/or inertia forces are significant. The impact of these stresses on deformations (board strain) was quantified using a specially designed test. Membrane stresses were also accounted for in a numerical (Finite Element Method) model developed and carefully validated in the course of this study. The model shows a very good agreement with test data. The nonlinearity of PCB deformation in shock, i.e. the fact that both bending moments and in-plane forces are present in the board has important implications on test metrology development and on correlation between the measured board strain and stresses in interconnects of surface mounted components. Of special importance is the impact that nonlinearity can have on development of transfer functions between strain measurements on system boards and strain measurements on test boards, which is also addressed in the paper.

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