Vehicle-Level Stripline Antenna Calibration Method Based on Field Strength Uniformity

Radiated immunity testing is an important component of electromagnetic compatibility testing for complete vehicles. However, we found that when using a stripline antenna for radiation immunity testing at frequencies of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.1 \text{MHz-30} \text{MHz}$</tex>, uneven distribution of electric field strength occurs. This has resulted in differences in testing results across different testing sites. In this paper, the stripline antenna is measured and simulated. Based on this result, we propose a new method to calibrate the electric field strength after comparing and analyzing the electric field strengths at different locations of the stripline antenna. The vehicle is known to have a large number of electronic devices located below the front windshield, so let's focus on this area. We set three calibration points at this location and calculated their average field strength as a basis for calibration. The experimental results show that the field strength uniformity is further enhanced in the frequency range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.1 \text{MHz}-30 \text{MHz}$</tex> by the field strength calibration with the calibration field method proposed in this paper.