Conformal antenna array radiation pattern synthesis by tilt correction to improve Direction-of-Arrival estimation accuracy

This paper, considering the tilt effect, presents a hemispherical antenna structure modeled by an improved conformal antenna array with the maximum angular coverage of the elevation axis to increase the Direction-of-Arrival (DOA) estimation accuracy. For this purpose, a multiface conformal structure with 3 different tilts and 13 directive circular patch antennas is designed in the Full Wave Simulation Software (HFSS). By optimizing the angles α and β as two key parameters in this design, nine different structures are constructed and their impacts on the DOA performance are carefully studied. The Cramer-Rao Lower Bound (CRLB), Multiple Signal Classification (MUSIC), and Root Mean Square Error (RMSE) algorithms are utilized to evaluate all constructed structures and chose the most improved structure for DOA estimation. At the end, it is shown that the proposed hemispherical antenna structure has a better performance than previous conformal designs for DOA applications and spatial resource positioning in which the maximum elevation angle coverage by the antenna is highly required. It is noted that the tilt optimization method proposed in this paper can lead to design a near optimal conformal antenna array structure for DOA estimation for a wide elevation angle coverage which can be considered for next works.