Dual-band Patch Antenna for Communication and Moisture Measurement of Coffee Bean

Abstract

The water content of the material affects the permittivity of the material, and changing the moisture content of the coffee bean changes the taste of coffee. The variation of the moisture content of coffee bean can be predicted by the change of the frequency and the return loss according to the change of the permittivity of the bean placed on the patch antenna. In this paper, dual-band patch antenna has been designed, a moisture measurement band 3.8Ghz $\sim 4$ Ghz that can measure moisture level of the material, and a transmit and receive band of WIFI 2.45GHz. This paper proved that the level of return loss changes from 3.6 to 4 GHz when the moisture content of coffee bean changes from 2 to 15% according to the simulation and measurement. By using this antenna, the moisture levels of rice and other beans can be measured and can be applied to various applications.