Design of a spiral antenna with coplanar feeding solution

A new design of spiral antenna is presented in this paper. The shape of the antenna is similar to that of the traditional Archimedean spiral antenna. However, this design allows to feed the antenna on the same plane, which is useful to conform the antenna on various surfaces. Two sources feed the structure. Loads placed along the arms and in the center of the antenna are used to decrease reflections at the end of the arms. Antenna behavior is studied using the software FEKO which is based on method of moments (MoM). This antenna shows the same characteristics as a traditional spiral antenna while being fed outside with coplanar feeding solution. The antenna is studied without a ground plane.