Soil electromagnetic parameters are related to physical and chemical properties, and mapping within-field variability provides valuable information for precision agriculture applications. Proximal soil sensing is convenient for this purpose due to its high spatial resolution. This thesis proposes the high-frequency electromagnetic induction modality for soil sensing in the frequency range from 3 MHz to 30 MHz, in which it is possible to measure both electrical conductivity and dielectric permittivity. The analytical model of the sensor above the double-layer homogeneous medium shows that the sensitivity to electrical conductivity and dielectric permittivity increases with frequency while the sensitivity to magnetic susceptibility is unchanged with frequency. The designed soil sensor consists of a shielded printed circuit board transmitter and receiver coils, which are separated and mutually perpendicular. The change in the height above the soil (liftoff) and unwanted electromagnetic, mechanical, and thermal influences on the sensor are analyzed theoretically and experimentally. The method to evaluate the effectiveness of the electrostatic shielding was derived by combining an equivalent circuit model of the sensor and measurements without the presence of the medium. The soil sensor was evaluated in the laboratory for the ranges typical for most soil types. The results agree with the numerical and analytical model and demonstrate the possibility of simultaneous measurement of electrical conductivity and dielectric permittivity. The accomplished scientific contribution of the thesis is: 1.) Model-based method for measurement of electrical conductivity and dielectric permittivity of soil using high-frequency electromagnetic induction, 2.) Analysis of unwanted electromagnetic coupling and interference rejection techniques, and 3.) Sensor geometry and electronic instrumentation for simultaneous measurement of soil electrical conductivity and dielectric permittivity using high-frequency electromagnetic induction.