A 2x1 compact UWB-MIMO antenna with two -10 dB impedance bandwidths of 2.6 GHz and 8.85 GHz is presented. The MIMO antenna dimension is 5.3 cm ´ 3.8 cm and is composed by two symmetrical rectangular patches, each one with a resonance frequency at 4 GHz. An EBG structure is introduced between the elements to increase de isolation and improve the MIMO antenna performance. The transmission coefficient of the MIMO antenna with EBG structure reaches a minimum of -28.9 dB at 8.18 GHz, and its maximum is -16.1 dB at 9.9 GHz. The impedance bandwidth is 5.9 GHz, and the maximum gain of the proposed antenna is 6 dBi.

Abstract. With the relation of Olinde Rodrigues-Cartan is obtained an expression for the Lorentz matrix, and it is transformed to a better form for the Newman-Penrose formalism, thus it is possible to realize rotations of the null tetrad of NP.