Biosensor Microstrip Antenna Design at 2.45 GHz for Bacteria Detection

Abstract

Bacteria found in food are very harmful to the health of the human body. This will cause various kinds of diseases. Therefore, food that is clean from bacteria is very important to maintain. Various solutions have been developed by researchers to provide a fast, sensitive, and cost-effective way to detect pathogens such as bacteria. The use of electrochemical biosensor devices is very commonly used to detect bacteria, viruses, fungi, and others. This approach is to identify infections quickly and accurately. In this study, the antenna biosensor was designed to detect bacteria. The antenna is designed to operate at a working frequency of 2.45 GHz (2.4 – 2.5 GHz) using a proximity coupled feed. The antenna is printed using Roger 3010 as a substrate material which has a thickness of 1.28 mm. Antenna biosensor testing was carried out using three (3) liquid samples, namely pure water (Aquadest), fresh milk, and Yakult. From the test results of the antenna without using a liquid sample, it was found that the antenna was able to work at an average frequency of 2.496 GHz with the best reflection coefficient at -16 dB. There is a shift in frequency compared to the frequency in the simulation. Tests using distilled water showed that there was no frequency shift, but testing with milk showed a decrease in frequency to an average frequency of 2.417 GHz. As for testing with Yakult, the frequency is on average at 2.491 GHz. As an initial hypothesis, the bacteria found in Yakult caused a slight shift in frequency from the original frequency. This is because fermentation in Yakult caused by bacteria results the viscosity to decrease compared to the viscosity of fresh milk.