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In this paper, an induction furnace employing with half bridge series resonant inverter built around IGBT as its switching devices suitable for melting 500 grams of brass is presented. Melting times of 10 minutes were achieved at a power level of approximately 4 kW. The operating frequency is automatically tracked to maintain a small constant lagging phase angle using dual phase lock loop when brass...
The optimal power transmission of a flat spiral coils are presented for wireless power transfer applications. It is a technique to increase the power transmission efficiency of magnetic field for wireless power transfer system by applying a flat spiral coils in conjunction with ferrite materials. The magnetic field distribution of flat spiral ferrite core materials and flat spiral air core will be...
The conventional rectangular horns have been used for microwave antennas a long time. Its gain can be increased by enlarging the construction of horn to flare exponentially. This paper presents the new technique for improving its gain for conventional horn without construction enlargement. The quadratic-shaped of woodpile Electromagnetic Band Gap (EBG) and the mushroom-like EBG have been utilized...
Nanostructures are expected to have more potential applications for the functional electronic devices and to obtain the novel opto-electronic properties. Therefore, many researches have been attempted to synthesize nanostructured ZnO in a controllable properties such as nanocrystal size, optical and electrical properties in order to gain the variety of microelectronic applications. This work studies...
This paper proposes the development of a Neural Network (NN) model for the prediction of the F2 layer critical frequency (foF2) at the magnetic equator over Chumphon (10.72°N, 99.37°E, dip angle 3.3°N), Thailand and then compared with the IRI model and the experimental ones. The feed forward network with backpropagation algorithm has been developed for predicting the foF2 values. The NN is trained...
In this paper, we investigate the parameterization of all robust stabilizing multi-period repetitive controllers for multiple-input/multiple-output time-delay plants. The multi-period repetitive control system is a type of servomechanism for a periodic reference input. When multi-period repetitive control design methods are applied to real systems, the influence of uncertainties in the plant must...
This work presents the combining of two methods, which are discrete Fourier transform spread (DFT-spread) and 2×2 space time block codes (STBC), to improve the system performance for polarization division multiplexing (PDM) coherent optical orthogonal frequency division multiplexing (CO-OFDM) communication systems. The system performances are generally measured by the unit of bit error rate (BER)...
The optical packet switching is widely used switching technology in current optical networks for high resource utilization. However it is not suitable for larger flows or real time traffic due to random packet loss and high delay variance. On the other hand, an alternate technique, optical flow switching (OFS), is suitable for the large flows. So to transport both types of traffic effectively, a hybrid...
This paper presents the design of a circularly polarized (CP) antenna for Radio Frequency Identification (RFID) reader using the ring slot microstrip antenna for Ultra High Frequency (UHF) band. The proposed antenna, which consists of a ring slot microstrip antenna with truncated U-slot, is placed on a FR4 substrate (εr = 4.5). The prototype antenna was fabricated with a total size of 100 × 100 ×...
This article presents 3 axis magnetotransistor based on the carrier recombination and deflection effect for detecting the magnetic field in BX, BY and BZ direction. The structure composes of four magnetotransistors along with x-axis and y-axis that has a common emitter while all collectors and bases are independent. The output is in the form of difference current of collector and base ΔICB. For vertical...
This article presents the enhancement of bandwidth for rectangular slot antenna with an H and T-shaped slot tuning. The bandwidth was increased from the original antenna by using the T-shaped slot tuning technique and adding the tuning stubs on the both sides of ground plane. The proposed antenna can be applied to ultra-wideband frequency range between 3.1–10.6 GHz based on the IEEE 802.15.3a standard...
This paper presents the design and realization of a low-noise, low-power, wide-dynamic-range CMOS logarithmic amplifier for cochlear implant system in a standard 0.18μm CMOS technology. The proposed logarithmic amplifier is based on the true piecewise linear function by using progressive-compression parallel-summation architecture. The overall circuit consumes only 9.1 μW from a 1.3 V single power...
We have developed a portable electronic nose (E-nose) based on eight metal oxide gas sensors for classification and prediction of meat freshness. In this study, the E-nose was applied to predict chicken freshness during different storage days. Principal component analysis (PCA) and artificial neural network (ANN) were used to analyze the experiment data. The PCA method can classify the chicken freshness...
An impedance matching technique for RF-MEMS switch based microstrip patch antenna is considered in this paper to improve the return loss and impedance bandwidth. It is observed that the impedance matching can be improved by using a lumped element based matching network. The impedance matching technique is performed by using Smith Chart and verified through Ansoft HFSS simulations. An inductor of 1...
This paper presents the design and concept of fuzzy logic controller analysis of two-output high-frequency series-resonant induction heater. The fuzzy logic controller is applied for non-linear load and unknown mathematical model as well as this prototype, which is used to control the duty-cycle of power switch to maintain current output. The power of the prototype can be controlled by using 3 branches...
This paper presents the study of the new exciting method for improving gain of the conventional conical horn at C-band frequency by using mushroom-like Electromagnetic Band Gap (EBG). The important technique of this paper is to use the basic mushroom-like Electromagnetic Band Gap (EBG) on circular plate and connected to waveguide/coaxial adapter. From the study, we found that such technique can provide...
One of the problems involved in the control of the real system is the time-delay of the control system. The time-delay generally makes the transfer function have an infinite number of poles, then it makes to guarantee the stability of time-delay control system and to specify the control characteristics difficult. One of the ways to overcome this problem is to use the modified Smith predictor. The...
This paper presents the forecast of the peak electricity demand (peak load) between 2014 to 2024 of the “Electricity Generating Authority of Thailand” (EGAT) by using Gaussian Process (QV), which used training data set since 2000 to 2013. The training data set composed of two important factors, including time on a monthly and the monthly of electricity peak load Moreover, it proposes a solution to...
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