Radar Vs. Ultrasonic Level Sensors: Key Differences And How To Choose

Level measurement is critical in industries such as water treatment, chemical processing, and bulk storage. Radar and ultrasonic sensors are two of the most common technologies. But which one is better for your application? This guide compares their operating principles, advantages, and limitations to help you make an informed decision.

1. Operating Principle

Radar Level Sensor

Uses microwave signals (radio waves such as 26GHz, 80GHz).

Measures the time of flight (ToF) of the reflected signal.

Not affected by dust, steam, or temperature fluctuations.

Ultrasonic Level Sensor

Uses high-frequency sound waves (typically 20-50 kHz).

Calculates distance based on the return time of the echo.

Performance may degrade in vacuum, foam, or turbulent surfaces.

2. Key comparison table

Parameters Radar level sensor Ultrasonic level sensor

Measurement range Up to 100+ m (80GHz models) Typically 0.25 m to 15 m

Accuracy ±1 mm to ±5 mm (higher frequency, better) ±3 mm to ±10 mm (affected by environment)

Beam angle 3°–15° (narrower = better focus) 10°–30° (wider = more interference)

Media compatibility Suitable for liquids, solids, slurries Not susceptible to foam, steam, and dust

Temperature range -40°C to +400°C (high temperature models) -40°C to +80°C (limited by sensor)

Pressure resistance Up to 40 bar (industrial models) Limited to 3–5 bar in most cases

Cost Higher initial cost ($500–$3000+) More affordable ($100–$1000)

3. When to choose radar or ultrasonic?

✅ Choose radar when:

You need high accuracy (e.g., chemical metering, custody transfer).

Environment has dust, steam or foam (e.g., cement silos, wastewater).

Media has low dielectric constant (e.g., LNG, solvents).

Tanks operate at high pressure/temperature.

✅ Choose ultrasonic when:

Budget is an issue (e.g., water tank monitoring).

Media surface is stable (no turbulence/foam).

Application is non-hazardous (no ATEX requirements).

4. Industry-specific recommendations

Petroleum

Radar: For ATEX areas, pressure tanks and crude oil.

Ultrasonic: Rarely used due to steam interference.

Water/Wastewater

Radar: Best for sludge, foam and large tanks (80GHz).

Ultrasonic: For clear water tanks (economical).

Food & Beverage

Radar: FDA-compliant models for sanitary environments.

Ultrasonic: limited to non-foaming liquids (e.g. milk storage).

Bulk solids (silos, grains, powders)

Radar: better suited for dusty environments (26GHz with horn antenna).

Ultrasonic: may fail due to material buildup on the sensor.

5. Common Mistakes: Avoid

Assuming ultrasonic is good enough for harsh environments.

Ignoring beam angle (resulting in false echoes in small tanks).

Ignoring dielectric constant (radar performs poorly if dielectric constant is less than 1.4 and not tuned).

Conclusion: Which should you buy?

Radar = high performance, harsh environments, accurate.

Ultrasonic = affordable, easy to apply.

Still unsure? Contact our engineers for a free consultation to meet your needs.

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Would you like a case study comparing real installations? Or a deeper understanding of FMCW radar and pulse radar?