Abstract: A polarized planar log periodic antenna is described that is simple in structure and compact in form and which in the dual circularly polarized form may serve as a direct replacement for less capable antennas in RF systems, such as countermeasures systems. An embodiment is characterized by a pair of relatively flat planar linear polarized log periodic antennas of the kind including a plurality of metal radiating elements, each of said radiating elements having the geometry of a circular arc; and the pair of antennas are attached in common to a planar dielectric base; one of said antennas being angularly oriented by ninety degrees relative to the other of said antennas with the radiating elements of one antenna interleaved with the corresponding radiating elements of the other antenna without direct electrical contact between the two antennas. Variations of the structure and novel RF feed line assembly are also described.