A New MM-Wave Backscattering Method for Estimating Water Content in Leaves To Minimize Demand on Water Resources

This paper is the first to propose a non-destructive measurement method based on reflection of mm-wave electromagnetic waves from leaves to continuously monitor water content in leaves. We propose to use backscattering, i.e., sending a sweeping sinusoidal signal toward a leaf and measuring the backscattered reflection to estimate water content in a leaf. This method allows for a hand-held device or a drone to perform measurements in the field. The proposed method is agnostic to the type of leaf observed and does not prescribe a required distance from which measurements are taken. Given appropriate transmit power and a suited narrow-beam antenna, this method can be applied at a wide range of distances. The results show that this approach allows for tracking water content in a leaf over time capturing fine grain details, can predict when water is added to the pot, tracks how the plant consumes water over time, and shows the optimal points in time to add more water.