Radar Level Gauges

Radar level gauges measure liquid or solid level without touching the product. A transmitter mounted on the tank roof sends microwave energy downward through the vapor space; the signal reflects off the liquid surface and returns. The gauge calculates the liquid level from the frequency shift or timing of the returning echo, delivering continuous measurement with no mechanical contact.

Cognesense’s radar portfolio uses FMCW (Frequency-Modulated Continuous Wave) technology, which continuously compares the emitted and reflected signal frequencies, achieving accuracy of ±0.5 mm. FMCW has largely replaced older pulse radar in precision tank gauging. Because nothing contacts the product, radar eliminates contamination risk, resists coating and buildup, and maintains reliable measurement through foam, condensation, vapor layers, and temperature extremes.

Installation centers on selecting and placing the antenna. The transmitter mounts vertically on a tank nozzle or stilling well, positioned away from walls, internal obstructions, and filling streams. Various antennas produce wider or narrower beam angles, improving signal focus in tall tanks or signal strength in challenging environments. Stilling-well antennas guide the signal in a contained path for applications where open vapor spaces create excessive signal noise.

One selection variable newcomers should understand: the product’s dielectric constant affects signal strength. High-dielectric liquids such as water and acids produce strong signal returns; low-dielectric hydrocarbons like LPG and light naphtha may require larger antennas or stilling wells to maintain reliable measurement.