Reliable Derivation of Automotive Antenna Gain Patterns from LTE Communication Parameters

Abstract

The number of wireless systems in modern vehicles is steadily increasing. The characterisation and evaluation of automotive radio systems is an important task in current research, especially in view of automated and connected driving. New methods to measure the radiation properties of antennas need to be developed, as the integration of antennas with frontends and signal processors proceeds rapidly. As a consequence, access to the antenna feed point may not be available, or require undesired modification of the system- under-test. This paper describes a method to determine the gain pattern of an automotive antenna by evaluating LTE communication parameters monitored by a standard LTE modem. The proposed approach allows for the measurement of the antenna in the installed state, as only a serial connection to the LTE modem is required, instead of RF access to the feed point. This method has been successfully verified in the virtual road simulation and test area for a horizontal cut of the gain pattern of an automotive LTE antenna at a frequency of 2655 MHz (LTE band 7). The gain pattern is virtually indistinguishable from that obtained with a conventional nearfield to far- field measurement technique.