A level gauge includes at least one antenna configured to transmit wireless signals towards a material in a tank and to receive wireless signals reflected from the material in the tank. The level gauge also includes a housing having an outer portion, a raised rim within the outer portion, an angled portion that extends between the outer portion and the rim, and a concave portion within the rim. The concave portion forms a crater within the housing. The at least one antenna is configured to transmit and receive the wireless signals through the concave portion of the housing.