On signal distortion in compact UWB arrays due to element interaction

Ultra-wideband (UWB) technology offers significant advantages in high resolution ranging due to the superior time-of-arrival (TOA) resolution. In order to allow direction-of-arrival (DOA) estimation from simultaneous TOA measurements multiple UWB antennas are required. This paper deals with systems characterized by a frequency bandwidth exceeding the center frequency (e.g. 3.1 to 10.6 GHz). Furthermore, it is focused on the special case where due to a restricted platform size the antenna spacing cannot be chosen large enough in order to avoid severe distortion in the angular dependence of the complex-valued transfer function caused by mutual interaction between the antenna elements. In this paper the impact of this signal distortion on the ranging accuracy is discussed. Furthermore, a novel approach for a first-order compensation of this drawback is presented.