Coplanar feeding solution for spiral antenna

A new externally-fed spiral antenna is presented in this paper. This antenna consists of two double arms and two sources in phase opposition are used to feed the device. This new design exhibits characteristics similar to that of the classical two arms center-fed spiral antenna. This is useful to conform the antenna on various platforms that do not allow access to the center of the spiral. The far field pattern is constant and symmetric about the antenna plane over the frequency range. Moreover, when use in an array, the bandwidth of the 2 times 2 arms spiral antenna is 37.5% larger than to that of the center-fed antenna.