Estimation of Real Ground Effect in Absorber-Based Automotive Measurements: Experimental Validation

Testing of antennas installed on vehicles are typically performed in large spherical near field systems truncated at or close to the horizon. The spherical scanning surface is usually terminated to a floor covered by absorbing material or to a conductive ground. The two scenarios are considered to either emulate a free-space or a perfect electric conductor (PEC) environment, respectively. The behavior of the vehicle antenna over realistic grounds, such as asphalts and soil, is often a desired information. It has been shown in previous publications that the realistic ground information can be estimated by post-processing using image theory in the post-processing on the free-space response of the vehicle. This technique has been implemented in the AnyGround post-processing tool. In this paper, AnyGround is validated by experimental investigation using scaled automotive measurement scenarios. As AnyGround is an approximation, the limitations and applicability parameters of the methods and the achievable accuracy is investigated.