Radar sensors

for level measurement with microwave signals

Continuous level measurement in liquids and solids with radar

In radar level measurement, the measuring device sends microwave signals from above onto the product, which reflects them. This non-contact measuring method has advantages, but above all disadvantages.

Radar sensors measure light and heavy bulk solids even in the presence of dust and noise, unaffected by build-up and condensation. Nevertheless, low fill levels in particular can cause the reflection of microwave signals to be influenced by the properties of the bulk material.

At MBA Instruments, we go one step further: We use state-of-the-art technology to set standards for precision and speed in level measurement. Our universal solutions are used where radar measurement reaches its limits.

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Monitor fill levels in silos and tanks

A level radar is a non-contact measuring device for level measurement in storage tanks or silos in the process industry. It works according to the FMCW method (Frequency Modulated Continuous Wave):

A transmitter beams radar pulses onto the bulk solids, whose surface in turn reflects the signals. The measured transit time is proportional to the fill level. The radar level switch can be used in silos up to 75 metres high. Typical areas of application include the food and construction industries, the chemical industry, plastics processing and steel production.

The technology is suitable for quickly measuring fill levels in a medium. The medium is not touched thanks to the principle of measurement with radar. This means that the sensors can even be used in corrosive or aggressive liquids.

Principle of measurement of non-contact radar measurements

The measuring method uses frequency-modulated continuous wave methods in various frequency ranges to measure the fill level in media such as bulk solids or liquids.

The measuring device sends radar pulses from an antenna in the direction of the medium to be measured. These pulses travel at the speed of light and propagate until they reach the surface of the medium.

As soon as the radar pulses hit the surface of the medium, a reflection occurs. This reflection occurs due to the change in the dielectric constant value (Dk value) on the surface of the material. The Dk value describes how well a material transmits or reflects electric fields.

The propagation time of the emitted radar pulse is directly proportional to the distance travelled. This means that the time it takes for the signal to travel from the antenna to the surface of the medium and then back to the antenna is measured. This propagation time is recorded extremely precisely.

The integrated electronics in the radar measuring device play a decisive role. It converts the measured transit times of the radar pulses into an analogue signal. This analogue signal contains information about the fill level of the medium.

The measuring device continuously transmits the current measured values of the fill level to the plant's control system. This provides the control system with real-time data to monitor and, if necessary, adjust the processes.

Areas of application for radar sensors

Radar measurement is still used in various areas of application.

Chemical industry

The chemical industry uses radar measurement to monitor the fill level of chemicals in tanks and containers because it involves the safe handling and storage of hazardous substances. Nevertheless, there are areas where the use of radar sensors proves impractical. For example, radar measurement is not the ideal solution for accurately determining the chemical composition of substances, especially when it comes to detecting impurities or chemical reactions in the liquids. In such cases, other measurement methods are advantageous.

Water and wastewater management

The water and wastewater industry relies on radar sensors to monitor water levels in reservoirs, clarifiers and sewers and to control pumping systems. Only rarely are the sensors in this area of application robust enough to withstand the site conditions. Radar sensors are susceptible to fouling, especially in wastewater systems where suspended solids, algae and debris are common. Contamination of the antenna can impair the measurement accuracy.

Limits of radar level measurement

Radar measurement is a suitable method for monitoring fill levels in liquids and solids. However, the measurement technology does not work for every measuring environment. In some applications, radar pulses are attenuated due to materials that absorb or scatter electromagnetic waves, which can lead to a loss of signal and therefore inaccurate measurements.

In systems with different tank sizes and shapes, the depth of field of the radar measurement can be a challenge. It requires a measurement solution in which the depth of field can be adjusted to optimise measurement accuracy in a wide range of application scenarios.

Radar measuring devices must function reliably in environments with strong temperature and pressure fluctuations. We offer robust solutions that can withstand even extreme conditions and ensure consistent measurements.

MBA Instruments has set itself the task of developing customised measuring devices that can be used as universal solutions for any application. Our measurement solutions are used where conventional measuring devices reach their limits. MBA Instruments utilises advanced signal processing techniques to overcome this challenge and ensure accurate measurements even in demanding environments.

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Our legacy products: MBA400 and MBA300

Our product range is constantly being expanded with new and further developments. Thanks to our innovative rotating paddle detectors, vibrating level switches and membrane switches, measurements with radar measuring devices are no longer necessary. Nevertheless, our discontinued MBA400 and MBA300 radar measuring devices are still widely used by customers.


Customers who still use our MBA400 measuring device can find product information here.

With the MBA400's radar measuring method, the fill level in narrow containers or containers with internals could be measured precisely and reliably. The level measurement did not require any contact with the bulk solids. A transmitter emitted radar pulses onto the bulk solids, the surface of which in turn reflected the signals. The measured transit time was proportional to the fill level. The radar level switch could be used in silos up to 75 metres high. Typical areas of application were the food, chemical and construction industries as well as plastics processing and steel production. Today we offer more innovative methods, for example for level measurement with rotary paddles.

Product information


Customers who still use our MBA300 measuring device can find product information here.

The continuous level measurement of the MBA300 is based on radar pulses that are reflected by the bulk solids. This method was mainly used in the food and construction industries, plastics processing and steel production. Thanks to radar technology, this type of level measurement did not require contact with the bulk solids. The radar level switch could be used in containers up to 15 metres high, e.g. on stockpiles, in silos and bunkers. Today, we offer improved level measurement methods.

Find out more about our universal solutions for level measurement:

MBA level switches

Do you want to monitor fill levels precisely and reliably?

Let's talk about the right solution for your individual measuring environment. Our universal level measurement solutions are customisable and offer precision and reliability, no matter what environment you are working in.

Jens Kirstein

Sales Manager

T +49 4106-12388 881

Other measuring principles of continuous level measurement

Ultrasonic sensors

Ultrasonic technology utilises ultrasonic waves that are emitted by a transmitter and recorded by a receiver. Ultrasonic level measurement is used in a wide range of applications. The measuring method is a proven and cost-effective solution for use in liquids and bulk solids.

Capacitive sensors

Whether in the plastics, chemical or packaging industry - capacitive sensors detect solids, bulk solids, liquids, metals and non-metals. Because they are non-contacting, non-reactive and work through container walls, there is no wear. Capacitive level sensors are developed for the detection of fill levels in hygienic environments.

Plumb bob sensors

In the field of grain and flour processing, a simple and reliable solution for level measurement tasks is required. Determining the fill level in closed, non-transparent containers, such as a silo, is necessary in order to be able to place repeat orders in good time and thus avoid production bottlenecks.

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