S. F. Khor

Experimental determination of the performance of rice husk-carbon nanotube composites for absorbing microwave signals in the frequency range of 12.4-18 GHz

Composites of rice husks and carbon nanotubes (RHC- NTs) are an innovation in improving the absorption of microwave sig- nals. Rice husks, which are an agricultural waste material, have been found to possess a signiflcant propensity for absorbing microwave sig- nals. Studies have shown that both rice husks and carbon nanotubes (CNTs) have high percentages of carbon. Thus, in this paper, we present the results of our experimental study in which we varied the ratios of rice husks and CNTs in the composite materials and deter- mined the dielectric properties of the composites and measured their abilities to absorb microwave signals. The experimental microwave

Analysis on monopole antenna for moisture determination in oil palm fruit using finite difference method

Finite difference analysis were applied to study the principle operation of monopole antenna for moisture determination in oil palm fruit at 2 GHz. The electromagnetic field interact with oil palm fruit on the interface between the antenna and oil palm fruit and cause a reflection. The reflection measurement is based on mismatch impedance or dielectric properties between two media. Reflection coefficient is used to quantify the level of reflection. The monopole antenna was made of RG405/U semi-rigid coaxial cable with an inner and outer diameter of 0.45 mm and 1.50 mm, respectively with 2.23 mm length of protruding conductor over 5.66 cm length of monopole antenna. This monopole antenna for moisture detection was compared with induced EMF method in terms of reflection coefficient at 2 GHz. The results show that the complex reflection coefficient measured using monopole antenna provides significant results to predict moisture content in oil palm fruit.

REFLECTION AND DIELECTRIC MEASUREMENT FOR SALINITY OF WATER USING MICROSTRIP LOOP ANTENNA AND DIELECTRIC PROBE

This study was conducted to investigate the feasibility of loop antenna in gauging level of salinity of water via electromagnetic wave reflection. High salinity cause adverse effect to environment. When high levels salinity of water diffuse into soil, it declines values of land for human and animal consumption. These impacts can cause tremendous monetary lost because the restoration of impairments is extremely costly. Therefore, a reliable salinity detection system of water source is crucial. In this work, reflection measurement was conducted using loop antenna in conjunction with network analyser for water salinity detection. Dielectric probe will be then used for dielectric characterization due to different water salinity. It comes to learn that the different level of salinity of water exhibit different dielectric properties through reflection measurement. The increment of salinity leads to increment and decrement of dielectric constant and loss factor, respectively. Similar observation can be found in reflection coefficient.