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.
Focus Horn Antenna
Meaning
Microwave horn antenna with an integrated lens directs high-frequency energy into a concentrated focal spot. Utilizing a focus horn antenna allows for precise material testing without the interference caused by reflections from surrounding lab equipment. This directional instrument is the primary sensor in free-space dielectric measurements of radome plastics.
Waveguide Feeding
High-frequency signals from the network analyzer pass through a hollow metal waveguide to feed the antenna. The focus horn antenna converts this guided wave into a highly directive free-space beam. By focusing the energy into a small spot, the antenna minimizes edge diffraction at the boundaries of the test sample.
Beam Convergence
Converging electromagnetic waves create a localized measurement zone where the wavefront is flat and parallel. This localized zone corresponds to the focal spot of the lens integrated into the focus horn antenna. Designing this focal spot carefully allows engineers to measure small material samples with high accuracy.
Calibration Accuracy
Characterizing millimeter-wave materials requires a calibration procedure to remove the effects of the cables and test antennas. Placing the focus horn antenna at the correct distance from the reference plane is critical to ensure that the mathematical phase correction holds. This precise physical setup ensures that the measurement of the transmission coefficient is highly repeatable.
It allows the test bench to isolate the electrical properties of the material under test from any external signal scattering.