Planar crossover for beamforming networks using Sierpenski gaskets

In this paper, a planar symmetric 4 port crossover formed from a square patch antenna with two sets of orthogonal feeds is presented. The operating frequency of the crossover is decided by the square patch. Electrical length of patch antenna is varied by summing various slots with alternative designs and sizes achieving frequency shift to lower side. The slots introduced are of different geometries like square, circle and diamond which are based on the Sierpenski gasket with a 3 phase of iteration in. This results in isolation better than 21 dB, transmission ~ 0dB for third iteration at the operating frequency. The proposed design can be used in beam forming networks and butler matrix.