Modeling and optimization design for RF humidity perception in storage environment

Abstract

Radio Frequency (RF) perception of humidity is the current research hotspot of grain condition monitoring for "three temperature and three humidity". In order to analyze the optimal detection parameters on humidity of storage environment, the Wireless Insite test platform is built to analyze the effects of antenna height, carrier frequency and grain and with different moisture content on Channel State Information (CSI) such as received power, path loss and time delay. The mathematical relations between the humidity and path loss, the humidity and time delay are deduced respectively. In simulation experiments, the frequency bands of 2.4GHz, 5GHz, 28GHz, 45GHz, 60GHz are selected. Study the changes of path loss and delay spread with humidity in the storage environment at different frequencies and antenna height. When the height of the transceiver antenna is set to 1m, the 28GHz, 45GHz and 60GHz millimeter wave signals are more sensitive to humidity changes, thereby which can provide more higher perception resolution of detecting humidity in the storage environment, compared with the 2.4GHz and 5GHz frequency bands. Besides, when space humidity is constant and the moisture content of wheat is changed, the arrival time of each ray in the channel at 45GHz is longer than that at 60GHz. The above work can provide reference for the application of RF sensing technology in the humidity detection scenario.