Design Fabrication and Testing of Patch Antenna Sensors

Abstract

The rapid growth of advanced wireless communication systems has driven significant advancements in sensor technologies, enabling their integration into various aspects of daily life. Furthermore, antennas, traditionally used for communication, have evolved to serve as sensors through backscattering, enabling wireless data transmission without the need for batteries. These antenna sensors may be used in agriculture to detect moisture levels, grain size and porosity, the humidity of rice and grains, and other factors like salt and sugar detection in water as well as the quality of water and food that aid farmers in selecting suitable crops and offer us food quality monitoring. This thesis presents a comprehensive study of the design, simulation, fabrication, and application of antenna sensors in various fields, including liquid quality analysis and agriculture. A compact complementary split-ring resonator (CSRR)-based rectangular microstrip patch antenna sensor is designed for detecting water quality and identifying milk adulterants such as water, caustic soda, sodium carbonate, ammonium sulphate, and urea. Additionally, microstrip and metamaterial-embedded patch sensors are developed to determine moisture content in grains, including rice, wheat, and pulses. The metamaterial sensor, operating at 4.5 GHz, achieved superior accuracy with mean relative errors (MRE) of 1.07% for rice, 1.13% for wheat, and 1.47% for pulses, outperforming the traditional microstrip design. Furthermore, a reconfigurable ring antenna sensor is designed to detect salt and sugar concentrations in water and various milk adulterants with low MRE values. These advancements highlight the potential of microstrip, metamaterial, and reconfigurable antenna sensors in industrial and consumer applications, ensuring quality control in food and beverages. newline