Microstrip antenna array with multi-polarization capabilities in the GSM1800 frequency band

The paper describes a linear microstrip antenna array, which is capable to operate with four variants of linear polarization, i.e. slant ±45°, vertical and horizontal one. The antenna is design to operate in the GSM1800 frequency band, and contains two separate input ports, which are sensitive to two mutually orthogonal slant polarizations. The principal matter under investigation concerns antenna radiation patterns, which can be obtained for an impinging EM wave of various linear polarizations. As usual, the patterns have been measured at both the antenna ports. In addition to this, the sum and difference antenna pattern have been measured. The paper reports a set of characteristics, which can be used to asses and better understand polarization capability of a multi-polarization antenna.