Measurements and Simulations for Validation of the Random-LOS Measurement Accuracy for Vehicular OTA Applications

Over-the-air (OTA) measurement techniques are essential to verify the performance of antennas and wireless devices. The random line-of-sight (random-LOS) measurement setup offers the advantage to test the OTA performance of antennas mounted on cars in existing, or new, semianechoic chamber and full-anechoic chamber. Hence, reusing currently available infrastructures together with a cost-efficient measurement setup will reduce OTA costs for the automotive industry. In random-LOS, a plane wave is synthesized in the test zone, where the far field of a radio base station is emulated. We present measurements and simulations of a random-LOS OTA setup operating at the 2.7 GHz band. We compare the cases when the emulated base station signals are generated by a single dual-polarized bowtie antenna, a uniform linear array of bowties and a uniform planar array of bowties. The evaluation of the standard deviation of the reference received signal in the test zone shows good agreement between measurements and simulations. We show with measurements that for a test zone with a radius of 0.5 m, the standard deviation can be less than 0.8 dB for the analyzed random-LOS OTA setup.