This article introduces the differences between 26G and 80G radar level meters and provides guidance for selecting the right one for specific working conditions.
Differences Between 26G Radar and 80G Radar
Radar level meters are measuring instruments based on the time-of-flight principle. With their advantages of non-contact measurement, strong anti-interference ability, high precision, low maintenance requirements, and long service life, they have gradually become the preferred equipment in many liquid level measurement scenarios.
Radar level meters come in various frequencies, such as 6GHz, 26GHz, 80GHz, and 120GHz. Generally, radar level meters can also be divided into high-frequency and low-frequency types. The 26G and 80G radar level meters are two common types of radar level meters. The main differences between the 26G and 80G radar level meters lie in their modulation frequency, wavelength, measurement accuracy, resolution, blind zone, and other aspects. Generally speaking, radar level meters with higher frequencies tend to have higher prices.
1. Modulation Frequency and Wavelength
Radar Spectrum
Microwaves refer to the range of electromagnetic waves with frequencies from 300MHz to 300GHz, and their corresponding wavelengths range from 1mm to 1m. The electromagnetic spectrum includes three frequency bands: decimeter waves (frequency range: 300MHz - 3GHz), centimeter waves (frequency range: 3 - 30GHz), and millimeter waves (frequency range: 30 - 300GHz). The relationship between wavelength and frequency is expressed by the formula c = λf, where c is the speed of light, λ is the wavelength, and f is the frequency.
26G radar level meter: Its modulation frequency is generally between 24GHz and 26GHz, with a wavelength of approximately 11.5mm, belonging to the centimeter wave band.
80G radar level meter: Its modulation frequency is generally between 78GHz and 82GHz, with a wavelength of approximately 3.75mm, belonging to the millimeter wave band.
2. Measurement Accuracy and Resolution
Typically, the higher the frequency (and thus the shorter the wavelength) of a radar, the higher its spatial resolution.
26G radar level meter: It belongs to the pulse radar (PTOF). The working principle of pulse radar is similar to "sonar detection": the transmitting unit periodically emits high-frequency pulse signals with an extremely short duration (usually nanosecond-level). When the pulses reach the surface of the medium, they are reflected, and the receiving unit records the time difference (Δt) between transmission and reception. Then, the liquid level is calculated using the formula "Distance = (Speed of light × Δt) / 2". Its circuit design is relatively simple and the cost is low. However, limited by the pulse width, there is a blind zone (usually 0.3 - 1m) in short-distance measurement, and the distance resolution is relatively low (generally ±5mm). It is suitable for scenarios with a wide measurement range and low precision requirements.
80G radar level meter: It belongs to the frequency-modulated continuous wave radar (FMCW). It emits continuous wave signals whose frequency changes linearly with time, and the relationship between the transmission frequency and time is a sawtooth wave or a triangular wave. When the echo signal is received, the transmission frequency has changed. The liquid level is calculated by measuring the frequency difference (Δf) between the transmitted wave and the echo, using the characteristic that "Δf is proportional to the distance". Due to the use of continuous wave signals, the FMCW radar has a small measurement blind zone, with a distance resolution of up to ±1mm, and stronger anti-interference ability, which can effectively distinguish the echoes from the liquid surface and nearby obstacles. However, its circuit is more complex and the cost is relatively higher, making it suitable for high-precision or short-distance measurement scenarios.
3. Beam Angle
A significant advantage of high-frequency microwaves is their extremely small beam angle. The beam angle of an 80GHz radar is usually only 3° - 5°, while that of a 26GHz radar reaches 10° - 15°. In narrow spaces or complex working conditions with obstacles, the 80GHz radar can better focus on the liquid level surface, reducing interference from the container wall or other internal structures. This feature makes it perform well in small storage tanks or when installed close to the tank wall.
4. Antenna Type80GHz radars usually adopt planar array antennas. Compared with the horn antennas commonly used in 26GHz radars, planar array antennas have stronger resistance to interference factors such as dust, steam, and condensation, and can maintain stable operation under harsh working conditions. For example, under stirring conditions, the liquid surface will produce eddy currents, foam, splashes, and even false interfaces, which put forward high requirements for the anti-interference ability and signal focusing performance of the measuring equipment. With its characteristics of short wavelength, narrow beam, and strong signal penetration, combined with advanced signal processing technology, the 80G high-frequency radar has become the mainstream solution for liquid level measurement in stirred tanks.
5.How to Select Between 80G and 26G Radar Level Meters?
Situations where 80GHz radar level meters are preferred:
Complex processes: There are agitators, heating coils, escalators, and other obstacles inside the tank.
Miniaturized containers: Reactors, small storage tanks, process containers (with a diameter of less than 1 meter).
Complex medium characteristics: Mediums that are prone to foam generation, volatilization leading to condensation, or liquids/solids with low dielectric constants.
High-precision measurement requirements: Used for trade settlement, precise batching, etc.
Restricted installation conditions: Insufficient short nozzle length, or unwillingness/inability to install waveguides.
Measurement of solid materials, especially particles and powders with low dielectric constants.
Situations where 26GHz radar level meters are preferred:
Standard large storage tanks: Such as reservoirs, crude oil storage tanks, sewage tanks, etc., with simple internal structures.
Limited cost budget, simple working conditions, and no special challenges.
Measurement of conventional liquids (water, oil, acid, alkali, etc.) and slurries with high dielectric constants.
6. Conclusion
In summary, with its excellent focusing ability and anti-interference performance, the 80GHz radar level meter is becoming the first choice in more and more application scenarios, especially in the process industry and complex working conditions. Through more intelligent installation and more stable measurement, it reduces the life-cycle cost. As a mature and reliable technology, the 26GHz radar level meter still has strong vitality in a large number of standard and simple liquid level measurement occasions due to its economy.
For radar level meters, a higher frequency is not necessarily better, nor is a lower frequency necessarily worse. When making a selection, factors such as the complexity of the working conditions, precision requirements, installation conditions, medium characteristics, and project budget should be comprehensively considered. The one that is suitable for the specific working conditions is the most appropriate.
