Free Space Quasi Optical Transmission Loss Calibration for Radome Materials
Calibrate free-space quasi-optical benches with time-gated TRL standards to prevent radome transmission loss from breaching radar EIRP regulatory limits.
Side Lobe Mask
Meaning
Radiation pattern limits define the maximum allowable power level of antenna emissions outside the primary boresight direction. A side lobe mask acts as a boundary that prevents an antenna from radiating too much energy into unwanted angles. This template is specified by regulatory standards to minimize interference between neighboring sensors and ensure efficient spectrum usage.
Manufacturers must test their antenna patterns against this mask to obtain regional wireless certifications.
Radiation Constraints
Unwanted energy radiation in side lobes can cause radar sensors to detect false targets and misinterpret the surrounding environment. Designing to a side lobe mask forces engineers to use aperture tapering and optimized feed networks to suppress these off-axis emissions. The limits are typically stricter at higher angles where emissions would interfere with adjacent vehicles or communication infrastructure.
Adhering to these tight emission limits requires high-precision manufacturing of the antenna arrays.
Antenna Integration
Interference with other systems can occur if the protective radome distorts the antenna’s designed radiation pattern. When testing a side lobe mask for an integrated radar module, the radome must be in place because it can increase the level of off-axis emissions. Any surface defect or thickness variation in the radome can cause the energy to scatter and exceed the mask limits.
The integrated assembly must therefore be designed as a single system to ensure compliance.
Compliance Sweep
Automated measurement systems in anechoic chambers are used to plot the angular radiation pattern of the fully assembled sensor. A compliance sweep compares the measured radiation pattern of the antenna with the defined side lobe mask across a range of azimuth and elevation angles. The software flags any point where the emitted power exceeds the mask limits as a failure.
This automated sweep ensures that every shipped sensor complies with the regulatory standards for electromagnetic emissions. The resulting test report is stored in the quality database to verify regulatory compliance before product release. By automating this process, the manufacturing team can quickly identify and reject any defective modules during high-volume production.