Contactless Sensing of Soil Electrical Conductivity Using High Frequency Electromagnetic Induction

Abstract

High frequency electromagnetic induction (HFEMI) soil sensors, operating in the frequency range up to 30 MHz, were previously proposed to increase the sensitivity to soil electrical conductivity and to make the sensitivity to soil dielectric permittivity significant. In this paper, we propose a compact HFEMI sensor consisting of shielded, mutually perpendicular PCB coils. We evaluate the sensor sensitivity to conductivity and discuss effects of dielectric permittivity and liftoff. The results agree well with the finite element analysis.