A PCB Environmental Sensor for Use in Monitoring Drought Conditions in Estuaries

2016 ◽  
Vol 13 (4) ◽  
pp. 182-187 ◽  
Author(s):  
Robert N. Dean ◽  
Frank T. Werner
Keyword(s):  
Electrical Conductivity ◽  
Parallel Plate ◽  
Printed Circuit Board ◽  
Salinity Gradient ◽  
Low Cost ◽  
Life Forms ◽  
Circuit Board ◽  
Linear Characteristic ◽  
Drought Conditions ◽  
Salinity Levels

Estuaries occur in coastal regions worldwide and are important habitats for humans and other life forms. These fragile ecosystems are susceptible to the effects of prolonged drought conditions, resulting in changes in the salinity gradient across the estuary, which can adversely affect life forms living in and around the estuary. Electrical conductivity sensors are used to determine salinity of aqueous solutions, including water samples from estuaries. Conventional electrical conductivity sensors, consisting of orthogonally mounted thin parallel plate electrodes, are fragile and difficult to clean. Low-cost commercial printed circuit board technology is presented here as a vehicle to realize a robust planar sensor for determining salinity. This sensor's planar electrode configuration is inherently simpler and less fragile than a sensor with two orthogonally mounted thin parallel plate electrodes. Prototype planar sensors were designed, fabricated, and successfully tested in a freshwater-seawater solution ranging from 100% freshwater to 100% seawater, emulating the salinity levels encountered across many estuaries. The sensor test data demonstrated a linear characteristic with both conductance (R2 = 0.9995) and salinity (R2 = 0.9969) as a function of seawater concentration.

A PCB Technology Moisture Content and Electrical Conductivity Sensor Probe for Agricultural and Horticultural Applications

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 000984-001011
Author(s):  
Robert N. Dean ◽  
Elizabeth Guertal ◽  
Adam Newby ◽  
Glenn Fain
Keyword(s):  
Electrical Conductivity ◽  
Plant Growth ◽  
Moisture Content ◽  
Test Data ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Conductivity Sensor ◽  
Irrigation Volume ◽  
Sensor Probe

Commercial printed circuit board (PCB) technology affords the realization of low-cost sensor probes for agricultural and horticultural applications. Plant growth can be optimized when the soil (in field crop applications) or the substrate (in greenhouse crop applications) properties can be measured and properly adjusted. Two important parameters are moisture content and electrical conductivity. Measuring moisture content allows the grower to better time irrigation for most efficient crop growth. Accurate moisture content measurement also allows the grower to apply sufficient irrigation volume for optimum plant growth while avoiding excessive irrigation volume. Likewise, measuring the electrical conductivity reveals useful information regarding ions in the soil or substrate, which can be used to optimize the application of plant nutrients or manage soil salinity. Commercial soil probes are expensive, which limits their widespread use in commercial applications. PCB probes, on the other hand, can be very inexpensive and can quickly be redesigned to modify the form factor for different applications. These sensors make use of the materials and processes inherent in commercial PCB manufacturing, including the FR4 substrate, patterned Cu cladding and soldermask. The non-conductive E-glass FR4 substrate is used as the rigid backbone of the sensor probe. The patterned Cu cladding is used for electrodes and signal traces. The polymeric soldermask is used as a thin insulating and moisture barrier layer. With these materials, insulated fringing field sensors can be realized on the surface of the PCB to measure moisture content, while exposed metal pads on the surface can be used to measure electrical conductivity. Additionally, the PCB probe is directly compatible with the integration of any desired integrated electronic components. Furthermore, the turnaround time for a new PCB sensor design can be as little as 24 hours at modest cost, making this technology economically superior to traditional sensor technologies, such as silicon based MEMS, where it can take months to realize a new design and be very expensive. A prototype sensor probe has been designed, fabricated and evaluated. Test data is analyzed, compared with test data from traditional sensor probes and presented.

A Novel Wideband transition from Substrate Integrated Waveguide to Rectangular Waveguide

2020 ◽  
Vol 10 ◽  
Author(s):  
Keyur Mahant ◽  
Hiren Mewada ◽  
Amit Patel ◽  
Alpesh Vala ◽  
Jitendra Chaudhari
Keyword(s):  
Rectangular Waveguide ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Single Layer ◽  
Circuit Board ◽  
Substrate Integrated Waveguide ◽  
Ka Band ◽  
Better Than ◽  
Millimeter Wave Circuits ◽  
Wideband Transition

Aim: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed Objective: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed. Method: Coupling patch etched on the SIW cavity to couple the electromagnetic energy from SIW to RWG. Moreover, metasurface is introduced into the radiating patch to enhance bandwidth. To verify the functionality of the proposed structure back to back transition is designed and fabricated on a single layer substrate using standard printed circuit board (PCB) fabrication technology. Results: Measured results matches with the simulation results, measured insertion loss is less than 1.2 dB and return loss is better than 3 dB for the frequency range of 28.8 to 36.3 GHz. By fabricating transition with 35 SRRs bandwidth of the proposed transition can be improved. Conclusion: The proposed transition has advantages like compact in size, easy to fabricate, low cost and wide bandwidth. Proposed structure is a good candidate for millimeter wave circuits and systems.

scholarly journals Highly Compact Through-Wire Microstrip to Empty Substrate Integrated Coaxial Line Transition

2021 ◽  
Vol 11 (15) ◽  
pp. 6885
Author(s):  
Marcos D. Fernandez ◽  
José A. Ballesteros ◽  
Angel Belenguer
Keyword(s):  
Printed Circuit Board ◽  
Low Cost ◽  
Coaxial Line ◽  
Circuit Board ◽  
Central Layer ◽  
Printed Circuit ◽  
Integrated Technology ◽  
Low Profile ◽  
The Many ◽  
High Degree

Empty substrate integrated coaxial line (ESICL) technology preserves the many advantages of the substrate integrated technology waveguides, such as low cost, low profile, or integration in a printed circuit board (PCB); in addition, ESICL is non-dispersive and has low radiation. To date, only two transitions have been proposed in the literature that connect the ESICL to classical planar lines such as grounded coplanar and microstrip. In both transitions, the feeding planar lines and the ESICL are built in the same substrate layer and they are based on transformed structures in the planar line, which must be in the central layer of the ESICL. These transitions also combine a lot of metallized and non-metallized parts, which increases the complexity of the manufacturing process. In this work, a new through-wire microstrip-to-ESICL transition is proposed. The feeding lines and the ESICL are implemented in different layers, so that the height of the ESICL can be independently chosen. In addition, it is a highly compact transition that does not require a transformer and can be freely rotated in its plane. This simplicity provides a high degree of versatility in the design phase, where there are only four variables that control the performance of the transition.

EFFECT OF HYDROTHERMAL TIME ON THE GROWTH OF ZnO NANORODS

2020 ◽  
pp. 84-91
Author(s):  
Hanh
Keyword(s):  
Printed Circuit Board ◽  
Low Cost ◽  
Cell Structure ◽  
Zno Nanorods ◽  
Zinc Nitrate ◽  
Circuit Board ◽  
Nitrate Hexahydrate ◽  
Hydrothermal Time ◽  
One Step ◽  
Surface Morphologies

In this work, ZnO nanorods (NRs) were successfully grown on printed circuit board substrates (PCBs) by utilizing a one-step, seedless, low-cost hydrothermal method. It was shown that by implementing a galvanic cell structure in an aqueous solution of 80 mM of zinc nitrate hexahydrate and hexamethylenetetramine, ZnO NRs can directly grow on the PCBs substrate without the assistance of a seed layer. The effect of hydrothermal time on the surface morphologies, and the crystallinity of the as-grown ZnO nanorods (NRs) was also investigated. The as-grown ZnO NRs also exhibited a significant enhancement in vertical growth and their crystallinity with 5 hour growth.

Nonlinear-Time-Dependent Analysis of Micro Via-In-Pad Substrates for Solder Bumped Flip Chip Applications

2002 ◽  
Vol 124 (3) ◽  
pp. 205-211 ◽  
Author(s):  
John H. Lau ◽  
S. W. Ricky Lee ◽  
Stephen H. Pan ◽  
Chris Chang
Keyword(s):  
Cross Sections ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Test Results ◽  
Pcb Assembly ◽  
Creep Analysis ◽  
Chip Scale Package ◽  
Time Dependent Analysis

An elasto-plastic-creep analysis of a low-cost micro via-in-pad (VIP) substrate for supporting a solder bumped flip chip in a chip scale package (CSP) format which is soldered onto a printed circuit board (PCB) is presented in this study. Emphasis is placed on the design, materials, and reliability of the micro VIP substrate and of the micro VIP CSP solder joints on PCB. The solder is assumed to obey Norton’s creep law. Cross-sections of samples are examined for a better understanding of the solder bump, CSP substrate redistribution, micro VIP, and solder joint. Also, the thermal cycling test results of the micro VIP CSP PCB assembly is presented.

A PCB Sensor for Magnetic Materials

2019 ◽  
Vol 2019 (DPC) ◽  
pp. 001323-001342
Author(s):  
Robert N. Dean ◽  
Lauren E. Beckingham
Keyword(s):  
Magnetic Materials ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Complex Impedance ◽  
Corrosion Products ◽  
Physical Contact ◽  
Circuit Board ◽  
Sensor Technology ◽  
Printed Circuit ◽  
Surrounding Environment

Printed circuit board (PCB) sensors are a sensor technology where the layout of traces on a PCB has been optimized so that the traces electromagnetically interact with the surrounding environment. These types of sensors can be manufactured at very low cost using standard commercially available low-cost printed circuit board fabrication. Exposed conductive electrodes on the circuit board are useful for measuring the electrical conductivity of the surrounding environment, and these sensors have been used in applications such as salinity measurement and dissolved ion content measurement of aqueous solutions. Insulated interdigitated electrode sensors are useful for capacitively analyzing the surrounding environment, and these sensors have been used to detect the presence of liquid water and to measure the moisture content of substances in physical contact with the sensor. Additionally, by measuring the complex impedance of the capacitive sensor over a wide frequency range, information concerning the chemical composition of the substance in contact with the sensor can be determined. In addition to conducive and capacitive PCB sensors, the third type of PCB sensor would be an inductive sensor. Although it is challenging to realize 3D coils in PCB technology, planar inductors can be realized in a single Cu layer on a PCB, and insulated from the environment using a cover layer of polymeric solder mask. This type of electrode structure can inductively couple with magnetic materials in close proximity to the sensor. A variety of magnetic materials exist, including iron, nickel and cobalt. Additionally, many alloys of these elements are also magnetic. Of particular interest are corrosion products with magnetic properties, such as iron(III) oxide, Fe3O2, also known as common rust. A thin layer of iron(III) oxide powder deposited on the sensor's active area results in a measureable increase in the sensor's inductance. As such, an inductive PCB sensor could be a low-cost option for detecting the presence of some corrosion products in its operating environment.

A Comparison of Immersion Gold and Tin Surface Finishes on Sensing Electrodes for PCB Environmental Saltwater Concentration Sensors

2016 ◽  
Vol 2016 (1) ◽  
pp. 000557-000562
Author(s):  
Robert N. Dean ◽  
Frank T. Werner ◽  
Michael J. Bozack
Keyword(s):  
Surface Finish ◽  
Printed Circuit Board ◽  
Chemical Constituents ◽  
Low Cost ◽  
Circuit Board ◽  
Testing Environment ◽  
Printed Circuit ◽  
Sensor Performance ◽  
Sensing Applications ◽  
Surface Finishes

Abstract Printed circuit board (PCB) sensors using low-cost commercial printed circuit board fabrication processes have been demonstrated for environmental sensing applications. One configuration of these sensors uses exposed electrodes to measure saltwater concentration in freshwater/seawater mixtures, through monitoring the resistance between the electrodes when they are immersed in the saltwater/freshwater solution. The lowest cost commercial PCB processes use an immersion Sn HASL surface finish on exposed copper cladding, including the sensing electrodes. This commercial PCB process has been demonstrated to make an effective, low-cost, short-lifetime sensor for saltwater concentration testing. The Sn finish, however, may not be optimal for this application. Sn oxidizes, which can interfere with sensor performance. Additionally, Sn and Sn oxides are potentially reactive with chemical constituents in seawater and seawater/freshwater solutions. An immersion Au (ENIG) surface finish is certainly less reactive with the atmosphere and chemicals likely present in the testing environment. However, an immersion Au finish increases the cost of the sensors by 30% to 40%. To investigate if the possible benefits of the more expensive Au surface finish are worth the extra expense, a study was performed where identical PCB sensors were procured from a commercial vendor with their standard low-cost Sn HASL finish and with their standard ENIG surface finish. Both sets of sensors were then evaluated in concentrations of seawater and freshwater, from 0% to 100% seawater concentration, using freshwater samples from a natural freshwater source near the coast where the seawater was obtained. Testing demonstrated an insignificant difference in sensor performance between the Sn HASL and the ENIG coated sensing electrodes. The results of this investigation indicated that for applications where the sensors will not be used for long periods of time, the added expense of an immersion Au surface finish is not worth the added cost.

Low-cost thin-film passive RFID circuits and detector system

2020 ◽  
Vol 12 (5) ◽  
pp. 356-366
Author(s):  
Salma El-Sawy ◽  
Wasim Nawaz ◽  
Mohamed Osama ◽  
Ahmet Tekin
Keyword(s):  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Flexible Substrate ◽  
Circuit Board ◽  
Detection Methods ◽  
Single Chip ◽  
Analog To Digital ◽  
Inductively Coupled ◽  
Passive Rfid

AbstractThis paper discusses the design of chip-less RFID tags of a standard pocket size of 69 mm by 156 mm. These tags are based on lumped elements of copper metal traces constructed on a thin polyamide flexible substrate. Moreover, a low-cost single-chip Bluetooth detector circuit system is demonstrated. Two different detection methods: variable coil load coupling and optical light intensity detection were combined to yield 256 unique ID codes. In the first method, by utilizing simple 4 MHz digital drivers and an integrated analog to digital converter (ADC) in the reader controller; various inductively coupled resonant loads corresponding to multiple distinct tags could be differentiated, yielding eight different (3-bit) ID codes. The additional via-based hole pattern reflectometer method creates additional 32 distinct levels (5-bit) utilizing 650 nm visible light-emitting diode and a simple trans-impedance operational along with the same analog ADC pins of a Bluetooth controller. The printed circuit board trace coil on the two-layer low-cost FR-4 waterproof sealed detector unit is simultaneously used as a Qi wireless power receiver to charge the120 mAh 2450 Lithium Polymer (LiR) battery. The device could remain operational for more than a month with a single charge; remaining connected with a mobile device and enabling 10 readouts daily.

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