Frequency, Temperature and Moisture Dependent Dielectric Properties of Chicken Manure Relevant to Radio frequency/Microwave Drying

Dielectric properties (dielectric constant & dielectric loss factor) of chicken manure in the temperature range of 10-70 degrees C and moisture contents of 15%, 25%, 35%, and 40% (wet basis), were determined using Agilent high temperature open-ended coaxial probe coupled with vector network analyzer in the frequency range 10 MHz to 14 GHz. It is observed that the dielectric constant and dielectric loss factor decrease with an increase of frequency at all temperatures. Moreover, these properties increase smoothly with temperature and moisture content up to similar to 40 degrees C, and beyond it, values increase abruptly at all frequencies. The penetration depths of the electromagnetic field in chicken manure samples were calculated at ISM (industrial, scientific and medical) frequencies of 13, 27, 40, 915, 2450, and 5800 MHz by making use of measured dielectric properties and it was observed that these depths decrease with increase in frequency at all moisture content and temperatures. The data of dielectric properties and penetration depths presented in this paper helps to develop the radio frequency/microwave applicators for providing dielectric heat treatment to chicken manure for various applications such as drying, disinfestation, pasteurization etc.