Direction-of-Arrival Estimation in Conformal Microstrip Patch Array Antenna

The direction-of-arrival (DOA) estimation of a conformal antenna array with directive elements is studied in this communication. The two-dimension Cramer-Rao lower bound (CRLB) is derived for a conformal antenna array by using the active directive radiation patterns of the array elements and compared with the isotropic ones. Moreover, the MUSIC method is used to confirm the CRLB results. Without loss of generality, the CRLB of a truncated hexagonal pyramid conformal array with seven patches is investigated which verify the significant effect of the directive elements in the DOA estimation accuracy rather than that of the isotropic ones. The simulation results prove that this conformal array achieves better DOA estimation performance rather than that of the planar array antenna especially at the horizon angles. Moreover, the conformal antenna array tilt angle is studied to achieve the optimum conformal array structure which depicts a tradeoff between the DOA estimation accuracy at low and high θ incident angles.