High Directivity Antenna Using a Modified Peano Space-Filling Curve

In this letter, a high directivity space-filling curve antenna is proposed. The antenna configuration is based on a second iteration Peano space-filling curve, where some modification is performed such that the final antenna operates as an array of dipoles having the same current phases. This is achieved by the insertion of a folded section of the wire antenna that provides a 180deg phase shift at some points, so that the current over the dipole segments is kept in phase. Three antenna structures are proposed and compared regarding; used area, directivity, radiation pattern and cross polarization. The proposed antenna structures have been simulated using the moment method simulation software IE3D. The designed antenna has a very narrow bandwidth (S₁₁<-30 dB ) around 3.5 GHz with maximum directivity of 18.6 dB, cross-polarization level >40 dB, and dimensions of 8/3lambdatimes4/3lambda.