Elevation and Azimuth Direction Finding by Two-Element Pattern Reconfigurable Antenna Array

An elevation and azimuth direction-finding (DF) method is presented by introducing the pattern reconfigurable antenna (PRA) into a two-element array. An equivalent multidimensional array is built by the two-element PRA array with switchable beams of same or opposite directions. With the introduction of same- and opposite-direction modes of PRAs, the elevation and azimuth angles are estimated by the methods of time-modulated array (TMA) and amplitude comparison, respectively. Meanwhile, a 2-D lookup table is built to correct the coning-error effect of the amplitude comparison. Compared with the conventional 2-D DF method with two orthogonal linear arrays, only a single linear array with not less than two elements is needed in the proposed method. Hence, it has the advantages of simple structure, compact size, and low cost. Simulated results are provided to verify the proposed 2-D DF method, and an S-band two-element PRA array is constructed to demonstrate its experimental feasibility.