A Microstrip Sensor for Determination of Harvesting Time for Oil Palm Fruits

The conventional method to determine ripeness of the oil palm bunch is by using the number or percentage of detached fruits per bunch. However the method has the disadvantage that it does not relate to oil quantity and quality. Previous work has shown a close relationship between oil content and moisture content during fruit development. Thus,the oil content and subsequently the time to harvest the fruit bunch can be determined from moisture measurements. In this study, a microstrip sensor has been developed to determine the optimum time of harvesting the oil palm fruits based on microwave attenuation. The sensor operating at 10.7GHz was fabricated using RT-Duroidsubtrate and is suitable for single fruit measurements. A theoretical analysis has been carried out to predict the variation in at tenuati on with moisture content in the fruit mesocarp. The propagation of the electromagnetic wave in the microstripis based on quasi - transverse electromagnetic mode (TEM mode) and the at tenuation is obtained by using signal flow graph technique

New developed formula to calculate the permittivity of ferrite-polymer composite

A new developed formula named the Habashi-Zul formula, based on the Maxwell-Garnett (MG) formula was fabricated and used to calculate the complex permittivity of the Sm-YIG in PVDF composite samples in the frequency range of 10 MHz to 1 GHz. The calculated permittivities results were compared with the measured values of each sample of Sm-YIG in PVDF composite samples and, with calculated results from various theoretical models including the MG, Looyenga, Bruggeman and, Sen Scala and Cohen. The Habashi-Zule formula presented higher accuracy as compared to other models

Estimation of dielectric constant for various standard materials using microstrip ring resonator

Microstrip ring resonator (MRR) is known for dielectric constant determination and many studies used Teflon as a standard sample. However, there are many other materials available which able to perform better or equivalence as the Teflon in calibrating certain dielectric constant measurement. This paper presents simulation of the MRR to investigate frequency shift of materials for dielectric constant estimation using the CST STUDIO SUITE 2016 software. The MRR was designed on RT/Duroid®5880 substrate (εr = 2.2, tanδ = 0.0004) with 50 Ω matching impedance where microstrip width, substrate thickness and ring mean radius were 4.893, 1.575 and 14 mm, respectively to resonate at 2.65340 GHz. Teflon, Polyimide, Isola FR408, Arlon AD250, Arlon AD270 and Gil GML1032 were alternately selected to be placed on top of the MRR as a standard sample to obtain the frequency shift. The frequency shifts for the above materials were 2.56932, 2.46149, 2.44680, 2.53748, 2.52007 and 2.48608 GHz, correspondingly. The differences in frequency shift were used in NetBeans IDE 8.1 algorithm of Java for dielectric constant calculation. The results indicated that Polyimide and Arlon AD250 had the lowest and highest mean percentage error of 0.83536 and 1.76505 %, respectively. Hence, Polyimide might as well be the most suitable candidate as a standard sample in MRR technique for dielectric constant measurement

Averaged kernel floor localization algorithm for multi-floor WLAN positioning

Multi-floor positioning is important especially to locate a user correctly in an urban area where multi-level buildings are located. In two-stage (vertical and horizontal) positioning, floor level is first determined prior to horizontal localization. Correct floor determination is crucial to ensure proper database selection for horizontal localization. This paper proposes a floor localization algorithm, the averaged kernel floor, which applies clustering technique and kernel density function to estimate the floor location of the user. The results show that the floor level could be determined accurately up to 91.7% in the tested environment. Additionally, the proposed algorithm has very low processing time of about 29 times lower compared to previous floor localization algorithms

Legendre multi-wavelets direct method for solving Fredholm integral equations of the second kind

In this paper,We use the continuous Legendre multi-wavelets on the interval [0, 1) to solve Fredholm integral equations of the second kind. To do so, we reduced the solution of Fredholm integral equation to the solution of algebraic equations. Illustrative examples are included to show the high accuracy of the estimation, and to demonstrate validity and applicability of the technique

Thermal-wave interferometry of gas-liquid applied to a thermal-wave resonator cavity technique

We propose the potential use of thermal-wave interferometry in measuring thermal diffusivities of two media with a thermal-wave resonator cavity technique. In the derived expression for a two-layer configuration, during cavity length probing of the upper medium, the physical and thermal properties of the lower medium were reasonably assumed to be independent of cavity length; hence each of the two slopes of signal versus cavity length actually determines the thermal diffusivity of the corresponding medium. In order to check the validity of the proposed model, we measure the thermal diffusivity of air and glycerol. A good linear relation of the amplitude and the phase with respect to cavity length in the thermally thick region of both media was observed, and the thermal diffusivities of air and glycerol obtained were close to the literature values. We suggest the potential application of thermal-wave resonator cavity technique to measure the thermal properties of a single-layer fluid in a general thermal condition where the advantage is that the signal-to-noise ratio is normally high compared to the thermally thick case. This can be achieved possibly by coating the pyroelectric transducer with a thermally thick solid material prior to any measurements

Estimating the permeability of ferrite-polymer composite via a numerical optimization method

Estimating the relative complex permeability of each component of samarium-substituted yttrium iron garnet nanoparticles in poly-vinylidene-fluride (Sm-YIG-PVDF) composite samples via a numerical optimization method is performed using a MATLAB program. The optimization is taken as the optimized parameters that yield a minimum sum for the absolute differences between the calculated impedance obtained by using the permeability calculated from Maxwell-Garnett (MG) formula and the measured equivalent one over the entire frequency range named the objective function (M). The guessed (estimated) ranges of the complex permeability are based on the measured values of each component of Sm-YIG-PVDF composite samples. The optimized (optimum) impedance values are in very good agreement with the measured ones for each composite and within the estimated ranges. More details on the optimization procedure and the permeability of different composition of the Sm-YIG-PVDF composite materials are illustrated

Effect of different subsectional basis and testing function in the method of moments for the scattering from two dimensional dielectric scatterers

Different integral equations are reduced to a system of linear equations via method of moments (MoM) where the different basis and testing function utilised are sinusoid/pulse, sinusoid/sinusoid, sinusoid/triangle, triangle/pulse, triangle/sinusoid and triangle/triangle method. A hollow/layered dielectric cylinder has been taken as a representative case study. Comparison is made on the convergence and accuracy due to different testing function where the mean relative error is investigated numerically to show the essential differences of different basis and testing function in the MoM using different implementation techniques and different boundary conditions. The Gauss quadrature and staircase approximation technique is used in calculating the impedance matrix elements. The different boundary conditions utilised is the exact and impedance boundary condition. Numerical results points out to the need to investigate the performance of other basis and testing functions for dielectric scatterers

Further extensions to rectangular dielectric waveguide technique for dielectric measurements

This paper describes a method to obtain the dielectric constant of materials using the rectangular dielectric waveguide technique in the WR-22 frequency band. By applying the solution of the wave equation, the actual dielectric constant for samples of small transverse dimensions can be directly recovered from the measured effective dielectric constant by a numerical technique. The method is very quick and simple and provides sufficient accuracy for most practical purpose