Matrix-construction calibration method for antenna arrays

The experimental evaluation of a calibration method (1994) developed for receive antenna arrays is presented. The method constructs a calibration matrix to compensate for unequal gain and phase responses at the array elements, mutual coupling among the elements, and small errors in element positions. The results showed that the method (1) reduced the deviation of the element gain patterns from the isolated-element patterns, the deviation of array beam patterns from the ideal patterns, the errors in relative element output powers and phases, and the errors in direction estimates using single-target and two-target array snapshots; (2) increased the alignment of single-target array snapshots with array steering vectors and the probability of resolving two targets as their angular separation decreased to zero; (3) produced essentially the same calibration matrix with different sets of calibration data; and (4) was highly tolerant to unknown interference in the calibration data.