Free Space Dielectric Property Extraction for Automotive Radar Polymer Enclosures
Precision W-band free-space extraction of polymer permittivity prevents radar boresight shift and avoids costly Class II Permissive Change re-testing delays.
Side Lobe Growth
Meaning
Increase in the amplitude of secondary radiation beams relative to the main beam occurs when an antenna is distorted or partially blocked. This side lobe growth is a major concern when integrating radar antennas behind protective radomes. The phenomenon occurs when non-uniformities in the plastic material scatter electromagnetic energy.
Aperture Efficiency
High-performance antenna arrays concentrate their radiated energy into a narrow main beam to maximize range and resolution. When side lobe growth occurs, energy is redirected away from the primary target area. This redirection reduces the overall gain of the antenna and lowers the signal-to-noise ratio for distant objects.
Signal Leakage
Energy redirected into side lobes creates a risk of receiving unwanted reflections from off-axis obstacles. This scattering of the beam allows the radar to detect reflections from the road or from adjacent lane barriers. This interference is interpreted by the sensor as real objects in the path of the vehicle, which can trigger false alarms.
Target Detection
Radar modules must distinguish between closely spaced objects to ensure safety on the road. If side lobe growth is high, the strong signal returned from a large truck can hide a smaller target like a motorcycle in the adjacent lane. This masking effect can cause the tracking algorithm to lose track of the smaller vehicle, presenting a serious hazard.
It can also lead to incorrect calculations of target size and position.