Thanaset Thosdeekoraphat

CCCIIs-Based First-Order All-Pass Filter and Quadrature Oscillators

This paper introduces a current-mode first-order all-pass filter (APF) and its application in quadrature oscillator (QO) based on CCCII. The proposed filter can provide inverting and noninverting all-pass functions with a same circuit topology, it uses two CCCIIs and one grounded capacitor. Moreover, the first-order all-pass filter was applied in current-mode sinusoidal quadrature oscillators with the design based on block diagrams. The introduced oscillators can provide four phase-quadrature signals which independently control the condition of oscillation (CO) and frequency of oscillation (FO). The proposed oscillators consist of three CCCIIs and two grounded capacitors. The proposed APF and QOs have high output impedance which can directly drive load without additional current buffer. In addition, they use only grounded capacitors which are very appropriate to future development into an integrated circuit. The results of PSPICE simulation program correspond to the theoretical analysis.

Development of magnetic shielding system for breast hyperthermia inductive heating

In this paper, the effect of cylindrical shield to heating area and location of induction heating for breast cancer hyperthermia treatment with hyperthermia inductive heating are presented. To determine heat distribution in the breast, which electric loss density is analyzed for various aperture sizes and radius of shielded cylindrical. It is a technique to control magnetic field intensity and relocate the heating area by using a cylindrical metal shielding with aperture. In the simulation, the inductive applicator is a ferrite core with diameter of 7 cm and excited by 4 MHz signal. The simulations show that the heating area can be effectively controlled by using the cylindrical shield with adjustable aperture size. The heating efficiency is reduced as the aperture size decreases. If the small heating area is needed, it may require longer treatment time. Nevertheless, the efficiency of heat can be increased by varying the radius size of shielding plate. Moreover, we investigate the position of heating region by varying the orientation of the ferrite core in x direction. The effect of horizontal position of the ferrite core to the heating location is also studied. Simulations show that the heating position can be relocated by changing the orientation of the ferrite core with cylindrical shield. The advantage of the magnetic shielding system is that it can be used to applied for prevent the effects of hyperthermia cancer treatment by induction heating.

The analysis and design of milk pasteurization system by using radio frequency electric fields

An analysis and design of dielectric heating system by using radio frequency electric field (RFEF) will be presented for the milk pasteurization process. It is a technique to transmit the electric fields into the intermediary by using the RFEF. To determine heat distribution in the dielectric loads, which electric field intensity are analyzed to be suitable for fluid and milk. In heating process, the heated material must be the polar molecules to perform the best efflciency of electric fleld transmission into the medium in order to increase the temperature of medium to greater heights. The electric fleld distributions on the lossy medium was analyzed using the CST EM STUDIO program. To investigate the difference of electric power on heating predicted by the theoretical model. In order to verify the simulation results. The proposed system is realized and experimentally examined. The applicator of RFEF with excited by 40 MHz signal and electric fleld strength of 1.6 kV/cm. In the results, it is found that the temperature of milk would be increased about 72.3°C, the process will be take approximately 2 minutes, and reduced population of bacteria 109,260 cfu/ml. Moreover, the investigation result revealed that the temperature of 71.7°C, it will be eliminated the bacteria in milk and extended shelf life of milk. The advantage of the principle of radio frequency electric flelds is that it can be applied to eliminate the bacteria in milk pasteurization.

Analysis and Design of Magnetic Shielding System for Breast Cancer Treatment with Hyperthermia Inductive Heating

An analysis and design of magnetic shielding system are presented for breast cancer treatment with hyperthermia inductive heating. It is a technique to control magnetic field intensity and relocate the heating area by using a rectangular shielding with aperture. The distribution of the lossy medium was analyzed using the finite difference time domain method. Theoretical analyses investigate whether a novel shielded system is effective for controlling the magnetic field distribution or heating position. Theoretical and experimental investigations were carried out using a lossy medium. The inductive applicator is a ferrite core with diameter of 7 cm, excited by 4 MHz signal and a maximum output power of 750 W. The results show that size of heating region can be controlled by varying the aperture size. Moreover, the investigation result revealed that the position of heating region can be relocated by changing the orientation of the ferrite core with shielded system in -axis direction. The advantage of the magnetic shielding system is that it can be applied to prevent the side effects of hyperthermia cancer treatment by inductive heating.

Optimization of Capacitor Copper Plate for Dielectric Heating to Eliminate Insect

This paper presents the optimization of dielectric heating by using capacitor copper plate material. It has dimension of 50x50 mm. and the distance between plates is 3 mm. This work is used for preheating of insect and pests. Considering the RLC resonance circuit and the power per heating area, the rice weevils are used for sample dielectric. While the power transfer is varied from 10 - 80 watt and resonance frequency at 65 MHz for analysis, the rice weevils are died when the power transfer are more than 70 watt in 1 second. Moreover, It the power transfer is decrease, the period of time is increase. Approximate 10 watt of power transfer, the plate copper has less power so the rice weevils are breaking. Therefore, the power transfer has an effect on the heating area, which is the relation of the fast time.

Design of Curved Patch Array Antenna for Small Missile Application

The design of curved patch array antenna for small missile application is presented. A thin copper plate antenna was attached a part of plastic pipe. This antenna is designed on cylinder metal object for such an application in military communication devices and antenna analysis was conducted by using the CST program. The frequency of a designed antenna was adjusted at 2.4 GHz. The proposed antenna is realized and experimentally examined, since it is small size, light weight, easy method fabrication and low manufacturing cost. In measurement, it is found that the propose antenna have the return loss was lower than-10 dB which covered frequency range 2.3 GHz-2.7 GHz. The average gain achieved in the propose antenna is about 6.13 dB over the operating frequency. The advantage of the proposed antenna is that it can be used to small missile for military application.