Direction finding system using symmetric-pair antenna arrays

A new type of direction finder that uses symmetric-pair antenna arrays is presented. Compared to conventional direction finding (DF) systems, no highly accurate phase or amplitude measurements are necessary, since symmetric-pair DF systems only measure polarities and determine both the azimuth and elevation angle of a received signal from that polarity pattern. The principle of direction finding with symmetric-pairs is outlined and algorithms are presented. Methods to improve the DF resolution for a given maximum antenna array size are discussed and a technique to cope with signals received around the grating lobe nulls of each antenna pair is introduced. The presented theory is confirmed by results obtained from a prototype DF system which operates at microwave frequencies