A multi-polarization multi-band Cross Spiral Antenna for mobile communication devices

A novel structure of simple multi-polarization antennas is presented in this paper. The antenna can be used in three or more mobile bands including a GPS band. It has been developed from the Cross-shaped Spiral Antenna: CSA, which is invented by the authors, by making gaps appropriately and being fed by a dipole element. Return-loss and axial ratios are improved comparing those of our conventional multi-polarization CSA. Moreover, the new structure has many advantages that it can be tuned to utilized frequencies and port impedances easier than the previous one. This study also shows the remarkable fact that it is possible to locate spiral parasitic elements close to a dipole element. Return-loss, radiation antenna patterns and axial ratios of the antenna are shown.