What is the detection range and blind zone size of an 80GHz radar level meter?

In the world of industrial-level measurement, two technical parameters dominate all discussions—the blind zone and the detection range.
These two factors determine how precisely a radar can track the surface level of materials inside a tank, silo, or container.

The Linpowave LPLM80, an 80 GHz millimeter-wave radar level meter, has been widely used in grain storage facilities, powder silos, and liquid tanks.
This article presents a factual overview of its blind zone and detection range, supported by Linpowave’s official manual and on-site measurement data collected in 2024.

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1. What Is a Radar Blind Zone and Why It Matters

Every radar sensor has a small section near its antenna where it cannot measure—this is the blind zone.
It occurs because the radar cannot distinguish between outgoing and returning signals during the transmit–receive switch.
In practical terms, if the radar’s blind zone is too large, it may fail to detect materials when the level gets very close to the sensor, resulting in inaccurate or missing readings near the top of a tank.

The 80 GHz radar operates at a higher frequency than traditional 24 GHz or 26 GHz devices, which means it emits a narrower beam and shorter pulses.
This higher frequency allows for a smaller blind zone and better performance in confined or dusty environments.

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2. Typical Blind Zone Values of Linpowave’s GHz Radar

Based on Linpowave’s LPLM80 technical documentation (V1.3) and verified site tests, the typical blind zone values are as follows:

• For liquids (such as water, oil, or ethanol): around 80–100 mm

• For solid grains (wheat, corn, rice): about 100–150 mm

• For optimized short-range models (range ≤30 m): as small as 40–80 mm

These values represent the effective distance below which the radar cannot detect returns.
In real-world conditions, however, the blind zone can slightly increase due to dust buildup, surface roughness, or dielectric variations.

The performance advantage of 80 GHz systems lies in the narrow beam angle (≈3°) and high signal-to-noise ratio, which allow more precise focusing on the material surface even in silos with uneven material distribution.

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3. How Environment Affects the Blind Zone

Grain Silos (Wheat, Corn)

In typical grain silos, the material surface is uneven and constantly changing as grains settle.
During testing, it was found that the effective blind zone increases by about 50% compared with liquid measurement.
This means that if the rated blind zone is 80 mm, the practical blind zone becomes approximately 120 mm.

Soybean Meal Silos

Soybean meal presents a more difficult case.
Its low dielectric constant and high dust concentration (above 200 mg/m³) cause strong signal scattering and attenuation.
Under such conditions, the blind zone can widen to 200 mm or more.
Installing an air-purge system—which periodically blows clean air over the radar’s lens—helps maintain reliable readings by preventing dust accumulation.

Environmental Compensation

Advanced algorithms in modern radar modules (like Linpowave’s dynamic compensation system) can partially correct for these effects, but physical cleaning remains essential for stable long-term operation.

External reference: ScienceDirect – Radar Level Measurement Overview

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4. Minimum Detection Distance: How Close Can It Measure?

The minimum detection distance represents the closest measurable range from the radar antenna to the material surface.
This distance varies with surface smoothness, dielectric properties, and signal strength.

In practice, a radar installed above a liquid tank can accurately measure down to 0.1 m.
For grains, 0.2–0.3 m is the realistic lower limit, ensuring the radar avoids interference from particle movement or flow during filling.
In low-reflection materials such as soybean meal, the effective range starts at 0.5 m.

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5. Maximum Detection Range: How Far Can It Measure?

The maximum detection range defines how deep or far the radar can measure while maintaining stable signal integrity.
This depends on factors such as antenna size, emitted power, and target reflectivity.

From Linpowave’s verified performance data:

Under clean environmental conditions, the LPLM80 radar maintains a stable detection range up to 60 m.
In large grain silos with good reflectivity, readings between 70 and 80 m remain consistent.
Custom configurations using a 120 mm lens antenna and a 3° beam angle can push the range to 120 m, suitable for tall silo groups or deep storage pits.

External reference: NIST – Millimeter-Wave Radar Characterization

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6. Comparison Between Blind Zone and Detection Range

These values demonstrate that the LPLM80’s 80 GHz radar design achieves both high sensitivity and long-range capability.
Its blind zone remains compact even in solids measurement, while its range is sufficient for nearly all medium to large industrial silos.

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7. Summary and Practical Insight

Based on the Linpowave LPLM80 product manual and 2024 field data, the 80 GHz radar level meter delivers an impressive performance balance:

• Smallest blind zone: about 80 mm (optimized version: 40 mm)

• Minimum detection distance: 0.1–0.3 m (depending on medium)

• Maximum detection range: up to 120 m under optimal conditions

In dusty grain silos or low-reflective materials, the radar’s effective parameters slightly widen, but it continues to operate within engineering tolerance levels.
For large or multi-silo systems, engineers can network multiple radars to extend monitoring coverage—a technique now being adopted in industrial grain storage automation.

For related insights, see:
👉 How Precise Is the Grain Silos’ 80 GHz Radar Level Meter?
👉 Linpowave Grain Silo Level Monitoring Series

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8. Frequently Asked Questions (FAQ)

Q1: What exactly is the radar blind zone?
A: It is the area directly below the antenna where the radar cannot distinguish return signals from its own transmission. No radar can detect within this zone, though advanced models minimize it.

Q2: How small can the LPLM80’s blind zone be?
A: Typically 80–100 mm, and as low as 40–80 mm in optimized short-range models (≤30 m).

Q3: Why does the blind zone increase in dusty or powdery environments?
A: Dust scatters radar waves and lowers the signal-to-noise ratio. The sensor compensates algorithmically, but physical interference still widens the effective blind zone.

Q4: What is the minimum distance this radar can measure?
A: Approximately 0.1 m for liquids, 0.2–0.3 m for grains, and around 0.5 m for soybean meal under heavy dust.

Q5: How far can the 80 GHz radar measure?
A: Standard units reach 60 m; upgraded configurations with larger antennas can achieve 80–120 m in ideal conditions.

Q6: Are these specifications fixed or dependent on installation?
A: They vary depending on antenna size, mounting position, and material properties. Field calibration ensures the best accuracy in each environment.

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9. Conclusion

The blind zone and detection range of Linpowave’s LPLM80 80 GHz radar level meter define its precision advantage in modern industrial sensing.
By combining narrow-beam 80 GHz transmission with refined signal processing, the device offers near-millimeter accuracy over a long detection range—even when dust and temperature variations challenge other sensor types.

For engineers designing or upgrading level monitoring systems, the LPLM80 provides a balanced solution: compact blind zone, broad detection range, and proven stability in real-world grain silos.

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References

• Linpowave, LPLM80 Product Manual (V1.3)

• Verified Field Data: Grain Silo Radar Level Measurement (2024)

• NIST – Millimeter-Wave Radar Characterization

• ScienceDirect – Radar Level Measurement Overview