The Effect of Electric Field Distributions on Mixture Dielectric Loads by Using Electrode Plate for Pests Controls in Agriculture Samran Santalunai, Chanchai Thongsopa, and Thanaset Thosdeekoraphat School of Electronic Engineering, Suranaree University of Technology, 111 University Avenue, Muang District, Nakorn Ratchasima 30000, Thailand Email: Santalunai.sja@gmail.com, {Chan, thanaset}@sut.ac.th Abstract—This research was conducted to analyze the effect of electric field distribution on mixture dielectric loads by using power ports on electrode plate for pest’s controls in agriculture. The electric fields were caused by the electric power on electrode plates to improve the electric field of dielectric loads. The dielectric loads of the rice and rice weevils were the target dielectric materials for analyzing the electric field distribution. To investigate the difference of electric power on heating predicted by the theoretical model, the electric field distributions were analyzed by using the finite difference time domain method. Theoretical and experimental investigations were carried out using dielectric load. The results demonstrated that the effect of the dielectric heating, the excitation source in symmetriclly was appropriate to the applications for the dielectric heating to cover the active area of heating. The advantage of the method is being able to be utilized for the dielectric heating applications to eliminate insects in the future. Index Terms—dielectric heating, dielectric load, power ports, electrode plate I. INTRODUCTION Dielectric heating technique is interested in the heating technology as the most important feature of thermal energy directly composed to the dielectric material with appropriate frequency range, thus, this technique does not affect other materials. The dielectric heating structure uses the frequency spectrum principle, which is applied as an electric field to transfer power into the dielectric material with polar molecules. The resonances of the molecules occurring in the dielectric material and dielectric heating are quickly and evenly generated. The dielectric heating is being applied in many applications [1]-[3], such as, dehydration industry and fruit pre serration industry. In addition, the dielectric heating can be also applied to eliminate the pests in agriculture since the structure of a pest is a liquid or polar molecule which can induce the electric field to heating [4]-[6]. Nowadays, grains derived from the harvests are treated by chemical fumigation to control storage pests (methyl bromide and phosphine) [7]-[9] before being shipped to domestic and international markets. Most people have Manuscript received April 7, 2015; revised November 12, 2015. concerned about the side effects of chemical fumigation on consumers and environment, we, the researchers, are interested to develop the methods to pests control by using the electromagnetic energies are Radio Frequency (RF) dielectric heating to control the pests in grains before being shipped. To generate the electromagnetic fields for dielectric heating, the plates were used as applicators to control generate electric field distributed between plates to heat the dielectric load. Many papers had reported the structures of the electrode plate with physically description of circular and square plates. Because the characteristic of the plate model and the distribution of electromagnetic fields were symmetrically and evenly electric field; which the pests and grains are flowed through the plate. Thus, the structures of rectangular plate are interested for conducting the research for pests control with gains embedded to influence the most effective applications because plate can expand the area and flow through the plate for the heating and increasing power ports are interesting. In this paper, we presented the effect of the electric field distribution on the dielectric load in the rectangular electrode. The electric field distributions caused the electric power on electrode plate. The dielectric loads were the grain and pests to analyze the rice and rice weevils as the targets of the main dielectric materials for an analysis of electric field distribution. The distributions of the dielectric load are analyzed by using the finite difference time domain method. The electrode plate of rectangular applicator had the diameter of 200 and 50mm. in width and length, respectively, and the input port powers used the 1 and 4 ports to analyze and control to compare the distribution. II. THE CONCEPT AND CONSTRUCTION OF DIELECTRIC HEATING This research presented the structure of dielectric heating for analyze electric field distributions shown in the Fig. 1. The diagram configuration of the generated oscillator frequency with 39 MHz, transferred into the electrode plate. The electrode plates consisted of two plates: the upper electrode plate is anode for generating International Journal of Electronics and Electrical Engineering Vol. 4, No. 4, August 2016 ©2016 Int. J. Electron. Electr. Eng. 305 doi: 10.18178/ijeee.4.4.305-308