SI-FMF11 FMCW Radar Level Transmitter 120GHz

FMCW Radar Level Transmitter with 120GHz fmcw, IP67 anti, can carry out 0.05m~30m Non-contact level measurement.

SI-FMF11 FMCW Radar Level Transmitter 120GHz

FMCW Radar Level Transmitter with 120G fmcw, IP67 anti, can carry out 0.05m~30m level measurement.
FMCW Radar Level Transmitter is based on the principle of FM continuous wave. FMCW refers to frequency modulated continuous wave. Use chirp high frequency signal.
120GHz FMCW Radar Level Transmitter, measuring distance up to 30 meters. The antenna is further optimized. The new and fast microprocessor can perform higher rate signal analysis and processing. The Radar Level Transmitter can be used for measuring high temperature and high pressure and other environmental liquids.

Sino-Inst offers a variety of FMCW Radar Level Transmitters for industrial level measurement. If you have any questions, please contact our sales engineers.

Features of SI-FMF11 FMCW Radar Level Transmitter

  • Millimeter wave radar. The measurement accuracy is up to ±2mm. The minimum blind area for measurement is 0.05m.
  • The smaller antenna size satisfies the measurement of more working conditions.
  • Multiple lens antennas. Smaller launch angle. More concentrated energy. Stronger echo signal. Under the same working conditions, it has higher reliability than other radar products.
  • It has stronger penetrability. It can be used normally in the case of adhesion and condensation.
  • Larger dynamic signal range. The measurement of low-dielectric constant medium is more stable.
  • Multiple measurement modes. The radar response time in fast measurement mode is less than 1s.

Specifications of SI-FMF11 FMCW Radar Level Transmitter

Measuring medium:Liquid
Measuring range:0.05m~30m
Process connection:G1 ½A/1½NPT thread/flange≥DN50
Process temperature:-40~80℃
Process pressure:-0.1~0.3 MPa
Protection level:IP67
Frequency Range:123GHz
power supply:Two-wire system (DC24V) / Four-wire system (DC12V~24V) / Four-wire system (AC220V)
Explosion-proof grade:Exia ⅡC T6 Ga / Exd IIC T6 Gb
Housing:Aluminum/plastic/stainless steel
Signal output:Two-wire system 4…20mA/HART protocol Four-wire system 4…20mA/RS485 Mod bus

FMCW Radar Level Transmitter 120GHz Applications

Solid measurement

  • Powder
  • Granule
  • Block
  • ※ Low dielectric constant plastic particles

Liquid measurement


What does Fmcw stand for?

FMCW, namely Frequency Modulated Continuous Wave.

FMCW technology and pulse radar technology are two technologies used in high-precision radar ranging. The basic principle is that the transmitted wave is a high-frequency continuous wave. Its frequency changes with time according to the law of triangle wave.

FMCW (Frequency Modulated Continuous Wave), the received echo frequency and the transmitted frequency change law are the same, both are triangular waves. There is only a time difference. Using this tiny time difference, the target distance can be calculated.

Extended Reading: Case: High Temperature Radar Level Transmitter for Melted Salt-Solar Photovoltaic Power Station

FMCW Radar Level Transmitter Working Principle

FM wave radar level sensor and distance formula:

Among them: C speed of light; fd Doppler frequency shift; fu triangle rising edge difference frequency; f0 FM initial frequency; T signal period; B signal bandwidth

The distance resolution depends on the frequency resolution of the DFT operation (Frequency Resolution). The frequency resolution of the DFT Fres is equal to:


T is the corresponding sampling time of the non-zero sampling value used for the DFT operation. If you use FFT + zero padding method to calculate the spectrum. T is the time corresponding to the sampled value of the non-zero-filled point.

The distance corresponding to the frequency resolution Fres is the range resolution Sres of the radar. Then, how to calculate the range resolution of the FMCW radar?

B: Frequency modulation width, unit Hz

T: Actual frequency modulation, in seconds

C: Speed of light, 3*10^8 meters/second

S: the distance between the radar and the object, meters

V: Frequency modulation speed, Hz/sec

t: wave propagation time, sec

V=BW/T  ②

t= 2S/C   ③

Assume that T is sampling during the entire frequency modulation period. And all sampling points are used for DFT calculation. According to ④ and ①,

which is

This is the calculation formula for the minimum range resolution that FMCW can obtain when the frequency modulation bandwidth is determined.

In actual use, the sampling time will be slightly shorter than the actual frequency modulation T. That is, Fres will be larger in value. So Sres will also become larger in value.

LFMCW, FMCW and Pulse radar

Radar (Radio detecting and ranging) means radio search and ranging. It is a device that uses various radio positioning methods to detect and identify various targets, determine target coordinates and other information.

In modern military and production, the role of radar is increasingly showing its importance. Especially in the Second World War, the “British” air battle between the British Air Force and the Luftwaffe made the importance of radar very clear.

The radar is composed of antenna system, transmitting device, receiving device, anti-interference equipment, display, signal processor, power supply and so on. Among them, the antenna is one of the key technologies for radar to achieve large airspace, multi-function, and multi-target. The signal processor is one of the core components of the radar with multi-function capabilities.

There are many types of radars, which can be classified in many ways:
(1) According to the positioning method, it can be divided into: active radar, semi-active radar and passive radar.
(2) According to the installation location, it can be divided into: ground radar, shipborne radar, aviation radar, satellite radar, etc.
(3) According to the type of radiation, it can be divided into: pulse radar and continuous wave radar.
(4) According to the work, it can be divided into long wave bands: meter wave radar, decimeter wave radar, centimeter wave radar and other wave band radars.
(5) According to the purpose, it can be divided into: target detection radar, reconnaissance radar, weapon control radar, flight support radar, weather radar, navigation radar, etc.

Pulse Radar

Pulse radar is a precision tracking radar. Each time it emits a pulse, the antenna can form several beams at the same time, and compare the amplitude and phase of the echo signal of each beam.

When the target is located on the antenna axis, the amplitude and phase of the echo signal of each beam are equal, and the signal difference is zero.

When the target is not on the antenna axis, the amplitude and phase of the echo signals of each beam are not equal, resulting in signal difference.

Drive the antenna to the target until the antenna axis is aligned with the target, so that the high and low angle and azimuth angle of the target can be measured.

The sum of the signals received by each beam can measure the distance of the target. In order to realize the measurement and tracking of the target.


FM continuous wave radar refers to a continuous wave radar whose transmitting frequency is modulated by a specific signal, such as weather radar.

FM continuous wave radar obtains the distance information of the target by comparing the difference between the frequency of the echo signal at any time and the frequency of the transmitted signal at that time.

The distance is proportional to the frequency difference between the two. The radial velocity and distance of the target can be obtained by processing the measured frequency difference between the two.

Compared with other range and speed measurement radars, the structure of FM continuous wave radar is simpler.

FMCW radar has rich technical experience, low transmit power peak required, easy modulation, low cost, and simple signal processing, so it is a commonly used radar system in automotive radars.

LFMCW radar, i.e., the carrier signal frequency changes linearly with time.

80G radar level sensor refers to frequency modulated continuous wave (FMCW) radar products working at 76-81GHz. It supports four-wire and two-wire applications. The large range of the product can reach 150m. The blind area can reach 8cm.

Because of its higher operating frequency and shorter wavelength, it is especially suitable for solid-state applications. It transmits and receives electromagnetic waves through a lens. It has unique advantages in high dust and harsh temperature environments (+200°C).

The main advantages of 80G high frequency radar level sensor are as follows:

  1. Based on self-developed CMOS millimeter-wave radio frequency chip. Realize a more compact radio frequency architecture. Higher signal-to-noise ratio and smaller blind area.
  2. Narrow 3° antenna beam angle. The interference in the installation environment has less influence on the instrument, and the installation is more convenient.
  3. The wavelength is shorter. It has better reflection characteristics on the solid surface. Therefore, there is no need to use a universal flange for aiming.
  4. Support remote debugging and remote upgrade. Reduce waiting time. Improve work efficiency.
  5. Support mobile phone Bluetooth debugging. It is convenient for on-site personnel to maintain work.

VEGAPULS 64 is a radar sensor for continuous level measurement of liquids. VEGA is the world’s leading manufacturer of radar level sensors. 80GHz radar level gauge VEGAPULS 64 has excellent performance.

Following VEGA, Sino-Inst also launched radar level sensor operating at 76-81 GHz.

The radar level sensor is divided according to the antenna type. There are the following types:
Cone antenna, parabolic antenna, horn antenna, long horn antenna.

The horn antenna adopts the working method of transmitting radar waves from a single point.
After the reflection of the horn surface, a divergent radar wave is formed. Usually used to measure the level of the vaulted tank that does not require a conduit. The measurement distance is smaller than that of a parabolic antenna.

Since the entire horn antenna extends into the tank, there is no big difference with the temperature in the tank. Therefore, there is basically no condensation on the antenna.

Guided wave radar level transmitter uses guided wave radar (GWR) technology. Based on the reflection of microwave on the surface medium. Through the probe, continuous level measurement of liquid and solid levels is completed.

A guided wave radar level transmitter is also called a wave-guided radar level sensor. They can measure both levels and the interface between two media. Through probe rod or cable, complete level contact types continuous level measurement. Such as Coaxial Probe Guided Wave Radar Level Transmitter. This is different from ultrasonic level measurement, which is non-contact measurement. A guided wave radar level transmitter is often used for tank level measurement. Including liquid and solid. Output 4~20mA/HART, so as to measure and control the level during production.

Extended reading: guided wave radar level sensor advantages and disadvantages

Ultrasonic Level Sensing sensors and transmitters are used for continuous, non-contact level measurement.

Ultrasonic Level Sensing is a low-cost liquid level measurement technology. Ultrasonic Level Sensing sensors and transmitters are used for tank or river level measurement. Ultrasonic Level Sensing does not need to contact the medium, can be continuously measured, low cost. Therefore, Ultrasonic Level Sensing is very popular among users. Ultrasonic liquid level sensors are available in general and intrinsically safe types. Output 4~20mA standard signal or output the measurement result to the secondary meter through RS-485. Meets the system’s automatic control.

More Featured Radar Level Transmitter


Radar level transmitter is an advanced non-contact measuring instrument. It is suitable for solid materials, process containers or strong dusts that are prone to crystallization and condensation. It has the advantages of low maintenance, high performance, high precision, high reliability and long service life.

It can adapt to harsh production environments such as high temperature, high pressure and steam. Even under extreme process conditions (pressure, temperature) and steam. Radar level measurement is also a safe solution.

Radar level transmitters can also be used in hygienic applications for non-contact level measurement.

Radar level transmitter versions can be used in different industries such as water/wastewater, food industry, life sciences or process industries.

Various antenna versions are available for various radar applications.

Radar Level Measurement and guide wave radar level measurement Image source:

Very short microwave pulses with very low energy are transmitted and received through the antenna system. The radar wave runs at the speed of light. The operating time can be converted into level signals by electronic components. A special time extension method can ensure stable and accurate measurement in a very short time.

Electromagnetic waves propagate in the air at the speed of light. The distance between the radar level gauge and the surface of the material can be expressed by the following formula:   

D = (1/2)*CT

In the formula:

D ———the distance between the radar level gauge and the surface of the material;   

C ———Speed of light   

T ———Pulse time.

Then the liquid level is:   L = E-D

In the formula:

L — liquid level;   

E ———The total height of the tank;   

D ———Air height.

Even in the presence of false reflections, the new micro-processing technology and the unique ECHOFOX- software can accurately analyze the level echo. By inputting the size of the container, the distance value can be converted into a signal proportional to the level. The instrument can be debugged with empty positions.

The radar is calibrated before leaving the factory. The wall can be tested before installation. The measured distance matches the measured distance.

There is also a test method, which is to send the 4-20mA value in the programmer to see if it is consistent with the value in the control room. After the test is completed, it will return to the normal test state from the power off.

Different settings in various mines.
Such as water, set it to liquid in the settings. There is almost no need to set other parameters.
If it is powder, then set the solid, cutting speed, material change, etc.
Adjust the universal joint flange;

Sino-Inst offers over 10 FMCW Radar Level Transmitters for level measurement. About 50% of these are float liquid level meters, 40% is the Solid level sensors.

A wide variety of FMCW Radar Level Transmitters options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of FMCW Radar Level Transmitters instrumentation, located in China.

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About KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects. Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.