Compact Interferometric Antenna Array for UWB Direction Finding

In this paper, a novel interferometer system for direction of arrival (DoA) estimation is presented. The design provides an extremely compact and lightweight interferometric panel that operates in an ultra-wideband (UWB) frequency range, from 2 GHz to 18 GHz. Two sets of sinuous antennas have been designed to properly manage the frequency spectrum of interest. In order to guarantee the detection of the majority of impinging waves, both sets of antennas work with a slant 45 (S45) polarization, ensuring good matching properties, high level of cross polarization isolation and stable radiation patterns. The design layout has been implemented to achieve an extremely compact structure maintaining a controlled phase error on each radiating element. Advantages in terms of size, weight and cost have been also presented. The complete interferometer structure has been manufactured and measured. Finally, a DoA estimation has been evaluated considering the measured patterns.