Wireless Underground Sensor Networks (WUSN) consists of buried sensors nodes which are expected to communicate through the soil. The significantly high attenuation caused by the soil properties is the main challenge for their feasibility. This challenge is accentuated with Impulse Radio Ultra-Wide Band (IR-UWB) WUSN because of the very low transmitted power. This paper first studies the impact of the soil on performances of a new small UWB buried antenna and then analyzes the effect of soil properties on the communication link from underground to aboveground. This study includes the effect of soil moisture, burial depth and frequency. Measurements are achieved in a sample of soil composed of standard pebbles used in railway (railroad ballast). The simulations and measurements results show that with short distances and low soil moisture underground to aboveground UWB communication is possible