Dual mode log periodic dipole antenna.

摘要

A dual mode log periodic dipole antenna (20) provides for sum and difference radiation patterns depending on the method of excitation. The antenna incorporates a support structure (22a, 22b) which secures a plurality of radiators (24) having three elements with successively increasing length. The center and right dipole elements of each radiator (24) and the center and left elements of each radiator (24) are alternately coupled together by separate conductive elements (32) in a crisscross fashion. Input ports (28, 30) coupled to the smallest radiator (24a) are driven with conventional hybrid coupler with either in-phase or out-of-phase energy at either lambda /2 or lambda . Sum and difference radiation patterns are achieved by appropriate section of the excited phase. Thus, this antenna (20) may be employed in monopulse or direction finding applications.