Analysis of broadband U-slot cut RMSA

The broadband rectangular Microstrip antenna has been realized by cutting the U-slot inside the patch. The slot is said to introduce a mode near the fundamental mode resonance frequency of the patch and realizes broadband response. The slot length is taken to be nearly half wave in length. In this paper, a broadband U-slot cut RMSA is studied for broadband response. The surface current distributions and the resonance curve plots over a wide frequency range have been analyzed. It is observed that the U-slot does not introduce any mode but modifies the higher order orthogonal mode resonance frequency of the rectangular patch and along with the fundamental mode realizes broadband response. The U-slot modifies the direction of surface current at the higher order orthogonal mode and therefore the radiation pattern over the operating bandwidth remains in the broadside direction.