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This research demonstrates the effect of the use of different Aurum (Au) interdigitated electrode (IDE) spacing on the performance of electrochemically reduced graphene oxide (ERGO) humidity sensor via electrodeposition method. Electrochemically deposition (ECD) is regarded as a green route approach where it does not require capping reagents or surfactant agents in the graphene oxide (GO) reduction process as well as a simple and economical synthesis procedure. In this experiment, four Au with different spacing used were 5um, 10um, 100um and 200um. The synthesis procedure was set up with cyclic voltammetry window parameter at sweep potential range 0.05V (start) to 0.05V (stop), vertex potential between the range -0.4V (upper) and -1.1 (lower), scan rate 5mV/s and 10 cycles in the aqueous solution graphene oxide (GO) for each sample at the 40°C water bath temperature. The fabricated samples with reduced graphene oxide (RGO) deposited on the surface of IDE were characterized on its humidity performance based on the results obtained in the current measurement (I-t) on the different relative humidity (RH) 40%RH-90%RH at 0.2V potential applied based on sensitivity, response time and recovery time. Moreover, the electrochemical properties ERGO was investigated via electrochemical impedance spectroscopy (EIS) with FRA measurement set up at applied voltage 0.2V for each fabricated sample. As a finding, 5um electrode spacing produce a great humidity performance with higher sensitivity, higher response time as well as higher recovery time. Whereas, the electrochemical impedance spectroscopy measurement showed the shorten the spacing the greater the ionic conductivity at electrode-electrolyte interface due to their low charge transfer resistance.

In this paper, a thin film were deposited on Interdigitated Electrodes (IDE) by using Electrochemical Deposition (ECD) method. Thin film consist of zinc nitrate (Zn(NO 3 ) 2 ) or zinc acetate (ZnC 4 H 6 O 4 ) precursors has been used in this work. Humidity sensors generally has three basic types which is resistive, capacitive and thermal. Materials such as porous ceramic, electrolytes, polymers are being used for humidity sensors. This research is to investigate the performance of the precursors as humidity sensor applications. Then, it's humidity sensing properties and electrical properties were observed. For the ECD process, different durations deposition time were set as the changes variable which are 500s, 2000s and 3500s. Electrical measurements were conducted at room temperature to evaluate the device's response on known relative humidity levels which is from 40%RH to 90%RH. It was found that, between the two precursors, sample with zinc nitrate precursor showing better performance in term of resistivity and also sensitivity towards humidity.

The solar photovoltaic (PV) system has become the key attraction for the generation of clean, renewable electricity. Nevertheless, performance varies due to different parameters and environmental factors. Therefore, a remote and real- performance is required to evaluate its performance. The Internet of Things (IoT) in the monitoring of the solar PV system has been implemented and its efficiency has been studied. The monitoring system uses real-time measured values to display power, current, voltage, temperature, and light intensity graphs, and it is also easy to track and view the database file to analyze the history of the collected data. The design work was divided into two main sections, hardware, and software. The hardware includes the creation of major units such as the power supply unit, the control unit and the sensor units while the software includes the database system and pulled the data out into private webpage and visualization on Grafana dashboard. This paper aims to create an IoT-based Solar Battery Monitoring System using two microcontrollers, Arduino UNO and NodeMCU. The data obtained will be stored in the local database and can be viewed through a personal web page that serves as a data log and through a visualization tool using Grafana. Throughout the system, users can easily track their solar PV system over the internet.

Low-power circuits are important for many applications, such as Internet of Things. Device variations and fluctuations are challenging their design. Random telegraph noise (RTN) is an important source of fluctuation. To verify a design by simulation, one needs assessing the impact of fluctuation in both driving current $\Delta {I}_{d}$ and threshold voltage $\Delta {V}_{\textsf {th}}$ . Many early works, however, only measured RTN-induced $\Delta {I}_{d}$ . $\Delta {V}_{\textsf {th}}$ was not directly measured because of two difficulties: its average value is low and it is highly dynamic. Early works often estimated $\Delta {V}_{\textsf {th}}$ from $\Delta {I}_{d}/{g}_{m}$ ( ${V}_{g} = {V}_{\textit {dd}}$ ), where ${g}_{m}$ is the transconductance, without giving its accuracy. The objective of this paper is to develop a new Trigger-When-Charged (TWC) technique for directly measuring the RTN-induced $\Delta {V}_{\textsf {th}}$ . By triggering the measurement only when a trap is charged, measurement accuracy is substantially improved. It is found that there is a poor correlation between $\Delta {I}_{d}/{g}_{m}$ ( ${V}_{g} = {V}_{\textit {dd}}$ ) and the directly measured $\Delta {V}_{\textsf {th}}$ ( ${V}_{g} = {V}_{\textsf {th}}$ ). The former is twice of the latter on average. The origin for this difference is analyzed. For the first time, the TWC is applied to evaluate device-to-device variations of the directly measured RTN-induced $\Delta {V}_{\textsf {th}}$ without selecting devices.

This work presents the effect of nitrogen (N 2 ) doped in aqueous solution of Graphene Oxide (GO) deposited onto the surface of the Aurum (Au) 200um spacing Interdigitated Electrode (IDE) via electrochemical deposition (ECD) method. Electrochemical deposition was the easiest and cost effective approach to synthesis of graphene oxide. It is an alternative green route to substitute the conventional Hummer’s method which is commonly used hydrazine for GO reduction. However, this chemical is highly toxic to the environment and any living creatures. In the ECD process, two Au samples were used, one doped with nitrogen and other without nitrogen. The cyclic voltammetry window parameter was set up at sweep potential from −0.4V (start) to −0.4V (stop), vertex potential between the range −0.4V (upper) and −1.1 (lower), scan rate 0.005V/s and 10 cycles in the 40°C water bath temperature for each of the samples. The fabricated samples were characterized using electrochemical impedance spectroscopy (EIS) to investigate the electrochemical properties of ERGO. The FRA measurement was set up to 1MHz frequency at different applied potential ranges in between 0.2V, 0.4V and 0.6V for each of the fabricated samples. Subsequently, the humidity performance was observed on the different relative humidity (RH) in between 40%RH-90%RH at applied potential 0.2V. Finding shows that the addition of nitrogen into aqueous GO contributes to the remarkable increase in ionic conductivity as well as high sensitivity response towards humidity.

A resistive-type humidity sensor based on Titanium Dioxide nanotubes was prepared. Anodization process is used to synthesize the Titanium Dioxide (TiO 2 ) thin film nanostructures. Titanium was used as an anode, while platinum as the cathode in an electrochemical cell filled with an electrolyte solution. Four different voltages for the anodization process are 10V, 15V, 20V and 30V. Each sample was fabricated at room temperature for 60 minutes. There are two types of electrolytes used in this study: with acid and without acid. From XRD analysis, oxide conversion is identified as a mixture of anatase and rutile at 10V. FESEM results showed that the surface morphology of titanium after being anodized at different voltages. The humidity sensing was set in the of 40%RH to 90%RH for 3 cycles. Amongst the sample without acid, the sample of 15V produced the highest humidity sensing level.

In this study, a new technique was used in order to detect honeybee’s authenticity. Pure honey and adulterated honey were characterized by using X-Ray Diffraction (XRD). To prepare the adulterated honey, sugar adulterants (glucose) was diluted into pure honey. The adulterant concentration is measured by 2% and 4% adulteration with 0% adulteration represents as the reference for pure honey. Ultraviolet-visible (UV-vis) spectroscopy was used to identify the absorbance of the honey with different solvents. Further research is still needed to test various combinations of methods to improve accuracy and the ability to simultaneously detect a wide range of adulterants in order to develop a portable test kit.

Power consumption is a key issue especially for the edge devices/units in an IoT system. Lowering operation voltage is an effective way to reduce power. As the overdrive voltage, Vg-Vth, becomes smaller, the device is more vulnerable to threshold voltage jitters. One source for the jitter is Random Telegraph Noises (RTN), which cause a fluctuation in both drain current, ΔId, and threshold voltage, ΔVth. Early works on RTN were focused on measuring ΔId and then evaluate ΔVth from ΔId/gm, where gm is transconductance. The accuracy of ΔVth obtained in this way is not known. The objective of this work is to assess its accuracy by comparing it with the ΔVth directly measured from pulse Id-Vg. It will be shown that the correlation between these two is poor, so that ΔVth must not be evaluated from ΔId/gm. This is caused by the device-specific localized current distribution near the threshold.

Negative bias temperature instability (NBTI)-generated defects (GDs) have been widely observed and known to play an important role in device’s lifetime. However, its characterization and modeling in nanoscaled devices is a challenge due to their stochastic nature. The objective of this paper is to develop a fast and accurate technique for characterizing the statistical properties of NBTI aging, which can be completed in one day and thus reduce test time significantly. The fast speed comes from replacing the conventional constant voltage stress by the voltage step stress (VSS), while the accuracy comes from capturing the GDs without recovery. The key advances are twofold: first, we demonstrate that this VSS-GD technique is applicable for nanoscaled devices; second, we verify the 15 accuracy of the statistical model based on the parameters extracted from this technique against independently measured data. The proposed method provides an effective solution for GD evaluation, as required when qualifying a CMOS process.

To predict the negative bias temperature instability (NBTI) towards the end of pMOSFETs’ 10 years lifetime, power-law based extrapolation is the industrial standard method. The prediction accuracy crucially depends on the accuracy of time exponents, n. The n reported by early work spreads in a wide range and varies with measurement conditions, which can lead to unacceptable errors when extrapolated to 10 years. The objective of this work is to find how to make the n extraction independent of measurement conditions. After removing the contribution from as-grown hole traps (AHT), a new method is proposed to capture the generated defects (GD) in their entirety. The n extracted by this method is around 0.2 and insensitive to measurement conditions for the four fabrication processes we tested. The model based on this method is verified by comparing its prediction with measurements. Under AC operation, the model predicts that GD can contribute to ~90% of NBTI at 10 years.

This work presents the synthesis and characterization of two different solutions of zinc oxide (ZnO) nanoporous and nanorod structured. Both are synthesized by electrodeposition technique by varying the effect of different duration of electrodeposition process and the effect of HMT presence in the solution. The crystallinity properties of the ZnO were affected by the duration of deposition which are 2000 s and 7000 s (without HMT) and 2000 s (with HMT). The structure of ZnO was successfully deposited and the peaks were obtained from the XRD results correspond to the ZnO with no other related peak were found for compound other than ZnO. The surface morphology obtained under FESEM clearly shows nanoporous structure (ZnO without HMT) and nanorod structure (ZnO with HMT). The UV testing proved that the result obtained for sensitivity shows great comparison between two different solutions. The increased level of sensitivity were due to the increase of time exposed to UV light. The improvement of time duration by using electrodeposition technique were increased based on the rise time and fall time. All of the combination results of the UV sensing is based on the performance sample deposited with ZnO.

As downscaling reaches nanometer scale, Hot Carrier Ageing (HCA) and Random Telegraphy Noise (RTN) are two important sources of device instability. Early works typically investigate them separately and treat them as independent phenomena. In reality, however, they occur simultaneously in a device and their interaction is not fully understood. In this work, we study the impact of HCA on RTN amplitude. It is found that for devices of average RTN, HCA only has a limited effect on RTN. For devices of abnormally high RTN, however, HCA can substantially reduce the RTN. The underlying physical mechanism is explored.

For nanometer MOSFETs, charging and discharging a single trap induces random telegraph noise (RTN). When there are more than a few traps, RTN signal becomes complex and appears as within a device fluctuation (WDF). RTN/WDF causes jitters in switch timing and is a major challenge to low power circuits. In addition to RTN/WDF, devices also age. The interaction between RTN/WDF and aging is of importance and not fully understood. Some researchers reported aging increasing RTN/WDF, while others showed RTN/WDF being hardly affected by aging. The objective of this paper is to investigate the impact of hot carrier aging (HCA) on the RTN/WDF of nMOSFETs. For devices of average RTN/WDF, it is found that the effect of HCA is generally modest. For devices of abnormally high RTN/WDF, however, for the first time, we report HCA reducing RTN/WDF substantially (>50%). This reduction originates from either a change of current distribution or defect losses.

This work presents the development of Ultraviolet (UV) Photodetector based on platinum doped niobium oxide (Nb 2 O 5 ) for enhancing UV Photodetector performance. The anodization duration was varied by using Ethylene Glycol and Ammonium Fluoride and observed by UV radiation with different voltage supply. The morphology of Nb 2 O 5 nanoporous was characterized by using FESEM. Metal contact with 30 nm thickness of platinum was used using Thermal Evaporator process. Different duration of anodized produces different sizes of nanoporous diameter that affected UV performance. Lastly, I-V characteristic was used to record the reading of UV performance for every sample substrate. The thinner the thickness of the substrate, the higher the performance of UV characterized.

Highly ordered Nb 2 Os nanoporous network via anodization for photocatalytic activity of methyl orange (MO) is presented. Persistent organic pollutants (POPs) are organic combinations that are unaffected to environmental degradation through chemical, biological, and photocatalytic processes. POPs have significant effects on human health and environment. This study will help reducing POPs. Anodization method is used to synthesis Nb 2 O 5 nanoporous structure. In this research, anodization duration is varies from 30 to 90 minutes to study the effect of durations on photocatalytic performance. To determine the rate of absorption of MO, UV-VIS Spectrophotometer is used to measure the absorption. The enhancement of photocatalytic property is desired in reducing contamination of POP in water produce by textile industries. The degradation of MO were influenced by the dimension of Nanoporous Nb 2 O 5 , showing that highly ordered nanoporous network as well as larger size of nanoporous Nb 2 O 5 have better performance of photocatalytic activity.

MATLAB is widely used in all areas of applied mathematics, in education and research at universities, and in the industry. MATLAB stands for MATrixLABoratory and the software is built up around vectors and matrices. This makes the software particularly useful for linear algebra but MATLAB is also a great tool for solving algebraic and differential equations and for numerical integration. Among MATLAB software main function is to produce a calculator to calculate the Link Budget System and the noise of the system. A link budget is accounting of all of the gains and losses from the transmitter, through the medium used (i.e. free space, cable, waveguide, and fiber) to the receiver in a telecommunication system. The purpose of calculating link budget is to investigate the system performance tied to operation threshold, to get the minimum power, Cmin that should be received at the demodulator input in order for communication to work properly with reading typically of 10 dB.By using this design, all the parameter (i.e. Effective Isotropic Radiated Power (EIRP), Path loss/Free space path loss, Effective aperture, Flux density, Physical aperture, Transmit gain, Receive gain, Transmit power and Receive power) can be calculated. Lastly, the purpose of calculating noise in satellite link system is to get noise temperature ratio and noise density ratio. A noise temperature ratio is a figure of merit used to represent the quality of a satellite or an earth station receiver. While, noise density ratio is one of the most important and most often used parameters when evaluating a digital radio system.

In this paper report a review on electroluminescent efficiency using a deoxyribonucleic acid (DNA) complex as an electron blocking layer (EBL) material in emitting organic light emitting diode (OLED). The resulting called BioLED showed a high luminous efficiency. The DNA-based BioLED was as much more efficient and brighter than their OLED counterparts. It is found the effect of EBL is to increase the device turn-on voltage for OLED structure. This is attributed to the fact that the DNA complex increases the series resistance of the device which is turn reduces the current through the device.

Ion Sensitive Field-Effect Transistor (ISFET) is a kind of sensor that able to differentiate the ion by replacing the gate of the FET with electrode and the membrane. Membrane acts as selector for the ions whereas the sensor detects the ions and converts it into electrical signal. However, the sensor has weakness to detect main ion from the interfering ion in the mixed solution when the ions have same characteristic. In this work, potassium ion (K+) and ammonium ion (NH4+) was used as the sample for both ions that have similar size. To overcome the problem, the sensor needs to be trained for pre-calibrate and pre-process by developing a model of Artificial Neural Networks (ANN) in MATLAB software. The ANN makes the model learn the pattern by the sample of inputs and outputs to estimate results or to get more accurate data. Backpropagation is used as the learning method of ANN model. The objective of this work is to develop ANN model for ISFET sensor that able to estimate the main ion in mixed solution by learning the pattern of the input and output of the sensor. The ANN model performance can be optimized by altering certain parameters in the learning algorithm. The results show that the model is able to predict with 97% accuracy and has strong and precise estimation ability with R-factor of 91.55%.

The deposition of Indium doped ZnO thin films using sol gel spin coating technique will be discussed in this paper. The concentrations of indium doping of the thin films were varied from 1.0–5.0 at. % indium. The effect of various doping concentrations 1.0–5.0 at. % indium on electrical, optical properties and gas sensing application were studied. The electrical properties were analyzed using I-V measurement (CEP2400). The optical transmittance and optical band gap were characterized by ultraviolet visible (UVVIS) spectrophotometer. Gold (Au) was used as a metal contact using electron beam thermal evaporator (ULVAC). The optical result show that the indium doped ZnO thin films revealed higher than 90% of transmittance value. The highest electrical resistivity was found 1.95E+04 £lcm at. 2% indium concentration. The optimum result of Indium doped ZnO thin films will be used for gas sensing application and gas sensitivity of the thin films will be extensively discussed in this paper.

Electroluminescence behavior of Poly [2-methoxy-5-(2-ethylhexyloxy) -1,4-phenylenevinylene] (MEH-PPV) as the emissive layer has been investigated in organic light emitting diode (OLED). The typical structure of polymer light emitting diode (PLED) is gold (Au) / MEH-PPV / ITO (Indium Tin Oxide). In this study, we investigated the EL behavior of single layer MEH-PPV at various applied voltages from 1 V to 5 V. The absorbance of MEH-PPV thin film and the EL spectra from 400 nm to 800 nm wavelength of the MEH-PPV device were discussed. The turn-on voltage is almost 1 V and the result showed that higher intensity with 5 V turn-on voltages.

CIGS (Copper (Cu), Indium (In), Galium Ga), Diselenide (Se2)) solar cell is the developing technology because of its low cost production and reliability of CIGS semiconductor itself. In this paper the difference of total current density and the IV curve of the CIGS solar cell will be shown when polysilicon was used as a contact window to replace aluminum doped zinc oxide (ZnO;Al) and the thickness of molybdenum and CIGS varied. The thickness of CIGS is varied to get the best thickness in order to obtain a good total current density since polysilicon is not widely used as an electrode in solar cell. Current density of CIGS solar cell will be shown in the figures at the result section.

In this work, ZnO thin films were deposited on glass substrates using spin coating method. Different annealing temperature from 400 to 550°C significantly distresses the nature of electrical and optical properties of ZnO thin films have been investigated. The effect of annealing temperature on optical and electrical properties of nanostuctured ZnO thin films deposited by spin coating method has been studied. The optical properties were characterized by ultraviolet visible (UV-VIS-NIR) spectrophotometer. The electrical properties were analyzed using I-V measurement (CEP 2000). Gold (Au) was used as a metal contact using electron beam thermal evaporator (ULVAC). The optical transmittance spectrums showed the average transmittance of ZnO thin film with different annealing temperature higher than 90% in visible wavelength region. The optical band properties of the nanostructured ZnO thin films were analyzed by UV Vis and Tauc method was accepted to estimate the optical gap and absorption coefficient. The resistivity of the film decreased as the annealing temperature increased from 400 to 550oC. The highest conductivity values of ZnO thin film was obtained at 500°C with value 0.000197 Scm-1. Moreover, the higher porosity was found at 400oC with value 57.5%. The higher porosity of ZnO thin film can be expected the high sensitivity for gas sensor due to the material has a comparatively large surface area.

The renewable-energy sector is fast gaining ground as a new growth area for numerous countries with the vast potential it presents environmentally and economically. Solar energy plays an important role as a primary source of energy, especially for rural area. This paper presents the design and development of high-efficiency dual-axis solar tracking system using Arduino platform. Furthermore, the ultimate objective of this project is to trace the maximum sunlight source to power the solar panel. The project is divided into two stages, which are hardware and software development. In hardware development, five light dependent resistor (LDR) has been used for capturing maximum light source. Two servo motors have been used to move the solar panel at maximum light source location sensing by LDR. Moreover, the code is constructed using C programming language and targeted to Arduino UNO controller. The efficiency of the system has been tested and compared with static solar panel on several time intervals, and it shows the system react the best at the 10-minutes intervals with consistent voltage generated. Therefore, the system has been proven working for capturing the maximum sunlight source for high efficiency solar harvesting applications.

This paper reports on the development of the electrical test setup for microfluidic field effect transistor (FET). Testing of the device commences during the fabrication process where various resistivity, grown layer thickness and other parameters are measured. However, these limited measurements do not give insights towards the final device performance. The final test is purely electrical and therefore a high current circuit to manually test the transistor characteristic of the microfluidic FET has been designed. The IV characteristic of the known metal oxide semiconductor field effect transistor (MOSFET) that is available in the market is the basis of the circuit design which is then used to characterize the microfluidic FET. Experimental results reveal the electrical responses from the test setup are consistent with the MOSFET behavior and an alternative method for the microfluidic FET characterization.

This paper presents the development of the prediction algorithm of lubricant degradation based on Beer Lambert's transmittance theory by using Multiple Linear Regressions (MLR). Recently, an increasing amount of wasted lubricant has been due to the unnecessary changing of lubricant even though the lubricant still remains its lubrication behavior. Therefore, a condition based technique is introduced to monitor the degradation parameters in lubricating oil by using optical approach. This work focuses on Total Acid Number (TAN) that has been identified as the main parameter in determining the lifetime of lubricant and it occurred at band location from 1,050–1,250cm−1 and 1,700–1,730cm−1. The best input parameter has been identified for sensor development and signal processing. Then, the prediction model is used to validate the measured and the predicted value of degradation. The high correlation between the predicted and measured data shows the prediction algorithm can be used for prediction purposes efficiently.

This paper reports on experimental results of radar measurements of basic targets using Ultra Wide Band (UWB) signals. The measurement was conducted in a laboratory room using UWB signals with frequency up to 1 GHz bandwidth. Targets used in this experiment are flat square plate and a square cube made from aluminum plates. It was observed that improved resolution of 5° was obtained with UWB signal, compared to using continuous wave (CW). Up to 3 dB reduction of side lobe fluctuation was also observed in specific incident angle.

The fabrication and characterization of static microfluidic transistors on p-silicon is demonstrated. A three photo mask level fabrication process, allows the construction of the microfluidic transistor with multiple channel widths which are 50μm, 100μm and 500μm. The basic device consists of two reservoirs connected via a channel which forms the basic fluidic circuit. Two doped regions will then be placed along the channel allowing the electrons to flow, comprising the electrical circuit. The results show that the fabrication technique used to build microfluidic transistors is relatively inexpensive and very much similar to present-day manufacturing technology that produces channel width ranging from 55 μm to 485 μm with depth ranging from 4.9 μm to 6.3 μm. Further work is carried out on the miniaturization of the micro-channel and the electrical characterization of the complete system.

This paper discussed about design and characterization of the Inter Digital capacitor. The main objective is to study the effects of width and spacing of the capacitor electrode on capacitance value. Water levels sensors are studied by using Inter Digital Capacitor (IDC) technique on Printed Circuit Board (PCB). IDC technique is used to make the capacitance measurement of the solution became more effective. This paper also presents simulation and experimental data to characterize the sensor. The result shows that the capacitance value is directly proportional to the electrode's width and inversely proportional to the electrode's spacing.

This paper presents a study of Planar Fringing Electric Field (FEF) as a pH sensor. Fringing Electric Field or FEF is widely used as a structure to detect capacitance in material under test (MUT). The study is carried out using Inter Digital Capacitor (IDC) technique on Printed Circuit Board (PCB). This study is to investigate the effectiveness of using IDC as to reduce the cost of making sensor. The study focused on the effect of using Ground, number, width and length of finger on the PCB. This paper also presents both simulation and experimental data to characterize the sensor.. The results show that the trend pattern of both simulation and experiment are similar and for the series IDC, the capacitance is decreasing as the number of series IDC increased.

In this paper, we present a design and simulation results of MEMS gyroscope using drive and sense electrode's voltage control to tune wide range resonance frequency that may yield robust vibratory MEMS gyroscope and at the same time retains the wide range of bandwidth. The design is of symmetrical shape for the proofmass and the branch-finger actuators. Branchfinger actuators in both drive and sense's mode also acted as stiffness tuner. Flexure shapes, although not exactly symmetrical, give us equal spring's constant in both x- and y- directions resulting in a matching resonance frequency. By properly arranging the voltage of drive and sense electrodes, we can have distributed drive-mode resonance frequency to overcome the sense-mode response shift due to changes of system parameters (e.g: fabrication imperfection or operating conditions). The capacitance in the sensing direction is measured between the perforated proofmass and perforated electrode plate underneath. From the simulation results we found out that the maximum range of bandwidth for the design is 358 Hz. Although we only varies the beam length, the experiment had shown that the design can give alternative to control mode mismatch.

This paper discussed about design, fabrication and characterization of pH transducer on printed circuit board (PCB). The main objective is to explore the possibility of pH transducer by using interdigital capacitor (IDC) on PCB and to study the performance of interdigital capacitor on PCB. The transducer can be used to sense the pH value for a solution. The term interdigital refers to pattern of fingers that is resembled by the shape and relative position of the electrodes. This transducer was fabricated by using PCB in order to prepared a lower cost pH transducer compared to the commercialize pH transducer. In addition, the result produces the capacitance changes over the time is 0.0189 µF/s. Moreover, the percentage of drift test is about 39.6% and the hysteresis is about 0.086µF and 0.895 µF. The results show that a good correlation coefficient was observed in sensitivity test. The correlation coefficient for sensitivity test is about 0.65. As long as the value of correlation coefficient is above 0.5 the transducer is good.

In this study, a fringing electric field (FEF)- capacitance based wireless soil moisture sensor has been designed, fabricated and tested to measure the volumetric water content (VWC) of soil for application in precision agriculture. Typically, the performance of the sensor is evaluated based on parameters such as penetration depth, signal strength, sensitivity and linear response. This paper presents the simulation results for the sensitivity analysis of the soil moisture sensor due to the effects of the electrode size and number of ground electrode. Simulations are conducted using finite element analysis (FEA) software, Finite Element Method Magnetics® (FEMM). From the simulation results, selected design of the FEF soil moisture sensors have been fabricated using printed circuit board technology. During testing, the measured capacitance from the sensor is connected directly to the device input using capacitance to digital converter. Data obtained from the sensor will be transferred wirelessly to the Zigbee coordinator; which is connected to the data base; using sensor mote. Testing revealed that the sensor is capable of detecting moisture from 1% to 80% VWC with a linear response. Test results obtained are then compared with FEMM simulations and benchmark sensor for validation purpose.

Mechanical geometry such as flexure's beam width, beam length, shin length and movable plate's size variations have effects on the resonance frequency because it's change the values of spring's constant and mass of the structure. This paper presents the effects of these mechanical geometries on resonance of MEMS out-of-plane accelerometer using Architect module in CoventorWare. Resonance frequency of the accelerometer is important because it determines the working frequency bandwidth of the accelerometers. Sensitivity analysis is carried out to determine which geometry most affects the device performance and needs to be controlled. An out-of-plane accelerometer with a fixed and a movable plate suspended by four flexures is used. Sensitivity by analysis shows resonant frequency decreases by 1.422% with 1% increase in beam length while the lowest changes is -0.061% of resonant frequency with 1 % increase in shin length.

In the design of a capacitive accelerometer, good mechanical sensitivity is desirable. A study of the optimization of flexure geometry in out-of-plane capacitive accelerometer for mechanical sensitivity enhancement is presented in this paper. The movable proof mass is suspended over the stationary electrodes by means of flexures anchored onto the substrate. The smallest possible spring constant of the flexures that will give the desired displacement was determined. Based on the spring constant's value, various combination of flexure length and width were selected and simulated using CAD software. The spring constant and displacement variations with the flexure dimensions at an applied acceleration was observed and analyzed. The modal and harmonic analysis were also simulated to ensure the linearity and the stability of the dominant mode of the device operation. Optimum results of the flexure geometry are presented and discussed.

A MEMS lateral capacitive accelerometer was designed and simulated. The accelerometer used in the study is based on gap-difference principle. It consists of 74 pairs of fingers and the proofmass suspended by two straight truss springs at both ends. Important parameters such as displacement, differential capacitance, harmonic response and sensitivity were studied and results presented. The shock resistance was also simulated to ensure the robustness of the device against external shock. The accelerometer is 40/spl mu/m thick and 0.6mm 0.7mm in size. It has a resonant frequency of 3.60 kHz at acceleration of 10g.