As we’ve discussed in previous blogs, multiple variables affect the real-world performance of millimeter-wave (mmWave) radar sensors. One critical yet often overlooked factor is thematerial of the target itself.
Different materials not only influence whether an object can be detected, but also directly impact detectionstability, range, and sensitivity. In this post, we’ll explore how target materials affect mmWave radar sensing and what you can do to optimize performance.
The Ideal Target: Dense, Flat, and Metallic
The optimal target for mmWave radar is aflat, radar-facing surface made from a dense material like metal. Industry testing typically uses a 10×10 cm carbon steel plate as the reference target due to its high radar reflectivity (high RCS – Radar Cross Section).
This kind of surface ensures a strong, stable echo. But in real-world applications, targets come in all shapes and materials—each with different radar visibility.
How Much Does Material Affect Detection Range?
Like inductive sensors, mmWave radar reacts very differently to different materials. Below is a reference chart from Linpowave’s lab data, showingtypical material reflectivity correction factors:
| Material | Correction Factor | Type |
|---|---|---|
| Carbon Steel | 1.00 | Ferrous metal (ideal target) |
| Aluminum | 0.40–0.60 | Non-ferrous metal |
| Brass | 0.35–0.55 | Non-ferrous metal |
| Plastic (ABS) | 0.25–0.50 | Low-density medium |
| Water / Skin | 0.20–0.45 | Soft tissue medium |
| Glass | < 0.10 | Radar-transparent (not a viable target) |
For example, if a radar sensor achieves a 5 m detection range with a carbon steel target, the same sensor might only detect a plastic object at around 1.5–2.5 m.
Shape and Angle Also Matter
In addition to material, theshape and orientationof the target strongly affect detection quality.
Radar sensors work best withflat, perpendicular surfacesthat reflect energy back to the receiver. Rounded surfaces, angled panels, or irregular geometries often scatter radar waves or absorb them, reducing signal strength.
This explains why the same object—like a human—can appear more or less visible depending on posture or angle.
Real-World Example: Human Fall Detection and Material Challenges
Linpowave’s LP series mmWave radar sensors are widely used in elderly care settings forfall detection and micro-motion sensing.
However, real-world deployments reveal several challenges:
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Thick clothing significantly reduces radar echo from the body
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Floor material (e.g., carpet vs. hardwood) affects detectability post-fall
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When a person lies down facing away from the radar, response time may be delayed
In other words—the material of the environment and the human body can critically impact radar performance, even when detection range is sufficient on paper.
How to Mitigate Material-Based Performance Drops
If material differences reduce radar detection performance in your application, here are some proven strategies:
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Avoid radar-invisible targetslike glass or low-density plastics
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Use a longer-range radar model, such as Linpowave’s LP-60
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Adjust sensor angle and mounting heightto maximize direct reflection
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Enable high-frame-rate modes and increase transmit powerin human sensing applications
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Use “factor-equalized” signal processing algorithmsto balance reflectivity differences across materials (available upon request)
Conclusion: Understanding Materials Is the First Step to Reliable Radar Sensing
Millimeter-wave radar is a powerful technology, offering advantages over IR or ultrasonic sensors in range, accuracy, and environmental robustness.
However, its performance is still heavily influenced bywhat it’s looking at.
By accounting for material type, geometry, and environmental context early in your deployment planning, you can select and configure radar systems for maximum reliability.
Need help selecting the right radar for your environment?
👉Contact the Linpowave technical team