In this paper, a single arm spiral antenna has been investigated about the characteristics of polarization and tilt beam. If a circumference length of spiral is bigger than a wavelength, it have a characteristic of varying maximum radiation beam direction. In addition, circular polarizations (RHCP, LHCP) can be variable by the feeding points (inner, outer). Also maximum beam directions tilt in different direction according to the circular polarizations, LHCP and RHCP. These characteristics of single arm spiral antenna are able to apply in the beam forming, diversity, MIMO application which has dual polarization using an antenna element.