Analysis of Butterfly-Shaped Compact Microstrip Antenna for Wideband Applications

Analysis of a butterfly shaped compact microstrip antenna with respect to the modes responsible for wider bandwidth is presented in this paper. A gradual development of the antenna from an antenna which is a combination of four circles of different radii to an antenna loaded with two slots within the structure without increasing the size of the antenna giving wider bandwidth is explained. Mode identification is done with the help of surface current distribution of the patches. The modes responsible for wider bandwidth are identified as TM21, TM22. A simulated bandwidth of 1.82 GHZ and broadside radiation pattern over the entire bandwidth is observed.