International Journal of Electric & Computer Sciences IJECS-IJENS Vol: 11 No: 01 27 119501-0808 IJECS-IJENS © February 2011 IJENS I J E N S The Behavior of the Dielectric Properties of Paddy Seeds with Resonance Frequencies Manjur Ahmed, Fareq Malek, Ee Meng Cheng # , Ahmad Nasir Che Rosli, Mohammad Shahrazel Razalli, Hasliza A. Rahim, R. Badlishah Ahmad, Rusnida Romli, Mohd Zaizu Ilyas, Muhamad Asmi Romli School of Computer and Communication Engineering # School of Mechatronic Engineering Universiti Malaysia Perlis (UniMAP) No 12 & 14, Jalan Satu, Taman Seberang Jaya, Fasa 3 02000 Kuala Perlis, Perlis, Malaysia Manjur Ahmed ( manjur_39@yahoo.com ), Fareq Malek ( mfareq@unimap.edu.my ) Ee Meng Cheng (emcheng@unimap.edu.my ), Ahmad Nasir Che Rosli ( ahmadnasir@unimap.edu.my ) Mohammad Shahrazel Razalli ( shahrazel@unimap.edu.my ) Hasliza A. Rahim ( haslizarahim@unimap.edu.my ) R. Badlishah Ahmad ( badli@unimap.edu.my ) Abstract-- The dielectric properties of two sample paddy seeds D219 and D222 were measured using microwave perturbation technique in a frequency range 9-12.2GHz of 33 frequency at interval of 100KHz, at a constant temperature (20 o C), same bulk density and moisture content (nearly same, 10.8% and 11% dry basis). The dielectric constant of D219 sample is higher than D222 before 9.8 GHz then decreases progressively when frequency increases. The loss factor of D219 also decreases sharply if compared with D222. The deviated values have been ignored as noise. The deviated values were presented due to the shape of the samples, unequal perturbation which attribute to full height insertion in cavity and shape perturbation of the cavity. This paper relates to a characterization system for various categories of paddy seeds to store for post harvesting. Index Term-- Complex permittivity, Cavity resonant technique, Q-factor, Resonance frequency, unequal perturbation, microwave treatment protocols. 1. INT RODUCT ION Complex permittivity of agricultural or biological materials is one of the most important characteristics for determining quality. It is important in determining the proper time for harvest and the potential for safe storage. It is also an important factor in determining the market price of agricultural commodities. In the processing of agricultural products, dielectric properties of the materials is important information for efficient processing, achieving desired behavior of the materials and in obtaining desired high-quality. The dielectric properties of agricultural or biological materials have much significance in processing of agricultural commodities and food. Concept and idea regarding the dielectric properties of agricultural commodities and insects enables us to understand the interactions between electromagnetic wave and vegetation, in order to inspire the development of RF treatments for agricultural products [1]. The dielectric property of agricultural products is a function of moisture content, frequency of the applied electromagnetic field, the temperature of the materials, and density and structure of the materials [2-9]. In granular and particulate materials, the bulk density of the air-particle mixture is another factor that influences the permittivity [4][10-14] . Rice (Oryza sativa L.) is the most important staple food in Asia and a major property for trading international and domestic market. Many studies have been conducted to explore the possibility of using electromagnetic energies to different agricultural commodities. However, most of the studies did not focus primarily to the post harvest rice seeds. Nomenclature Q quality factor index c for empty cavity and index s for sample inserted into cavity ε complex permittivity ε′ dielectric constant ε″ dielectric loss factor resonance peak frequency frequency bandwidth difference f resonance frequency, index c for empty cavity and index s for sample inserted into cavity V volume index c for empty cavity and index s for sample inserted into cavity r 2 regression coefficient