How to Select a Radar Level Sensor?

Introduction

Radar level sensors have become one of the most reliable technologies for continuous level measurement in industrial applications. Compared with ultrasonic, float, or hydrostatic sensors, radar sensors provide higher accuracy, longer measuring distances, and excellent performance in harsh environments such as dust, steam, condensation, and high temperatures.

However, selecting the right radar level sensor is not always straightforward. Different radar technologies are designed for different applications, and factors such as the measured medium, tank structure, installation conditions, and required accuracy all influence the selection.

This guide explains the different types of radar level sensors and provides practical advice to help you choose the most suitable solution for your application.

 

What Are the Main Types of Radar Level Sensors?

Radar level sensors can be divided into two main categories: Non-contact Radar Level Sensors and Guided Wave Radar (GWR). Both technologies use microwave signals to measure level, but they differ in how the signals travel and interact with the measured medium.

 

Non-contact Radar Level Sensors

Non-contact radar sensors transmit microwave signals through free space toward the material surface. The reflected signal is analyzed to calculate the level.

Common operating frequencies include:

26GHz

60GHz

80GHz

 

Among these, 60GHz and 80GHz have become the mainstream choices because they offer better focusing ability, improved signal processing, and higher measurement reliability than earlier 26GHz designs.

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Guided Wave Radar (GWR)

Guided wave radar sensor also uses microwave technology, but instead of transmitting signals through the air, the microwave pulse travels along a probe (rod, cable, or coaxial tube). The signal reflects when it reaches the product surface, allowing the instrument to determine the level.

 

This design provides stable measurement in applications where the signal benefits from being guided directly to the medium.

 

Comparison of Radar Level Sensor Types

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How to Select a Radar Level Sensor

Choosing the right radar level sensor depends on several key factors.

1. What Medium Are You Measuring?

The type of material is the first consideration. For liquids, such as water, wastewater, chemicals, fuels, and edible oils, both non-contact radar and guided wave radar can provide reliable measurement.

 

For bulk solids, including grain, cement, fly ash, sand, coal powder, and plastic pellets, non-contact radar is generally the preferred choice because it measures without contacting the material and performs well in dusty environments.

 

2. Consider Tank Size and Measuring Distance

Tank dimensions influence both installation and performance.

Tank Type	Recommended Technology
Water Storage Tank	Non-contact Radar
Chemical Tank	Non-contact Radar or Guided Wave Radar
Fuel Storage Tank	Non-contact Radar
Grain Silo	Non-contact Radar
Cement Silo	Non-contact Radar
Small Process Vessel	Guided Wave Radar
Bypass Chamber	Guided Wave Radar

 

Large storage tanks and silos usually benefit from non-contact radar, while guided wave radar is often suitable for compact process vessels.

 

3. Evaluate Process Conditions

Environmental conditions can significantly affect measurement performance. Choose non-contact radar when the application involves:

Dust

Steam

Condensation

Corrosive media

Sticky products

Internal obstacles such as agitators or ladders

 

Choose guided wave radar when the application involves:

Heavy foam

Interface measurement between two liquids

Small vessels with stable installation conditions

 

4. Consider Maintenance Requirements

Maintenance costs should be evaluated over the entire service life of the instrument.

Non-contact radar offers several advantages:

No contact with the measured medium

No moving parts

Minimal maintenance

Long operating life

 

Guided wave radar may require periodic probe cleaning if product buildup occurs.

 

When Should You Choose 80GHz Instead of 60GHz?

Both 60GHz and 80GHz radar technologies deliver excellent performance for industrial level measurement. However, their strengths differ depending on the application. Choose an 80GHz radar sensor if your application involves:

Bulk solids such as grain, cement, fly ash, sand, or plastic pellets

Narrow nozzles or confined installation spaces

Long measuring distances

Dusty environments

Tanks with internal structures that may cause signal interference

Applications requiring very high measurement accuracy

 

The higher operating frequency enables a narrower beam angle, allowing the radar signal to better avoid tank walls and internal obstacles.

 

A 60GHz radar sensor is often sufficient for:

Water storage tanks

Municipal water systems

Wastewater treatment

Diesel and fuel tanks

Chemical storage tanks with simple geometry

General industrial liquid level measurement

 

For many standard liquid applications, a 60GHz radar sensor provides an excellent balance between performance and cost.

 

Recommended Radar Technology by Application

Application	Recommended Technology	Suggested Frequency
Clean Water Tanks	Non-contact Radar	60GHz or 80GHz
Wastewater Tanks	Non-contact Radar	60GHz or 80GHz
Fuel Storage Tanks	Non-contact Radar	60GHz or 80GHz
Chemical Storage Tanks	Non-contact Radar	60GHz or 80GHz (depending on installation)
Grain Silos	Non-contact Radar	80GHz
Cement Silos	Non-contact Radar	80GHz
Plastic Pellets	Non-contact Radar	80GHz
Fly Ash Silos	Non-contact Radar	80GHz
Interface Measurement	Guided Wave Radar	N/A
Heavy Foam Liquids	Guided Wave Radar	N/A
Small Process Vessels	Guided Wave Radar	N/A
Bypass Chambers	Guided Wave Radar	N/A

 

Conclusion

Selecting the right radar level sensor starts with understanding your application rather than choosing the highest frequency available.

 

For most industrial liquid level applications, non-contact radar operating at 60GHz or 80GHz provides reliable, maintenance-free measurement with excellent long-term stability.

 

If your application involves bulk solids, narrow installation spaces, dusty conditions, or requires higher measurement precision, 80GHz radar is often the preferred choice due to its narrower beam angle and superior signal focusing.

 

For interface measurement, heavy foam, or compact process vessels where a probe-guided signal offers advantages, guided wave radar remains an excellent solution.

 

By evaluating your medium, tank geometry, process conditions, and maintenance expectations, you can select a radar level sensor that delivers accurate and dependable performance throughout its service life.

 

 

Radar Level Sensor FAQs

1. Is 80GHz radar always better than 60GHz radar?

Not necessarily. For many standard liquid applications, 60GHz radar provides excellent performance. An 80GHz radar sensor is particularly advantageous for bulk solids, narrow installation spaces, dusty environments, and applications requiring a narrower beam angle or higher accuracy.

 

2. Which radar technology is best for grain silos?

Non-contact radar is generally the preferred solution. An 80GHz radar sensor is especially suitable because its narrow beam angle helps reduce interference from silo walls and internal structures.

 

3. Can radar level sensors measure corrosive liquids?

Yes. Non-contact radar is especially well suited because it does not come into contact with the measured medium.

 

4. What’s the difference between a radar level sensor and an ultrasonic level sensor?

See our previous article here.

 

5. Can one radar level sensor be used for both liquids and solids?

Yes. Many radar level sensors can measure both liquids and solids. However, the sensor configuration may differ depending on the application. Solid materials such as grain, cement, and coal usually require a sensor with a narrow beam angle, strong signal processing capability, and longer measuring range.

 

6. Does the dielectric constant of the medium affect radar measurement?

Yes. The dielectric constant affects the strength of the reflected radar signal. Materials with a high dielectric constant, such as water-based liquids, reflect radar signals strongly and are easier to measure.

Low dielectric materials, such as plastic pellets, oil, and some powders, require optimized radar technology and installation.

 

7. Can radar level sensors work in tanks with mixers or agitators?

Yes, but proper selection and installation are important.

 

8. Do radar level sensors require calibration?

Yes, but radar sensors usually require minimal calibration compared with other technologies.