WIDE-BAND PATCH ANTENNA ARRAY WITH LOW CROSS-POLARIZATION CHARACTERISTICS

In this letter, a two-element wide-band patch antenna array with low cross-polarization is presented. The patch is excited by a magnetic-coupled loop. The two elements are placed symmetrically about the center of the array. Compared to the conventional feeding structure, the proposed feeding structure has the advantages of simple structure and much lower cross polarization. Parametric studies show the usefulness of the proposed feeding structure. Prototypes for the element and array have been fabricated and tested. The antenna array can achieve an impedance of 29.1% for VSWR < 2 and a stable gain around 11.2 dBi. Unidirectional radiation patterns with low cross polarization less than -18 dB within the 3-dB beamwidths are obtained. The height of antenna is about 0.12 lambda (where lambda is the free-space wavelength referring to the center frequency of the working band). Moreover, the proposed antenna is dc grounded, which is suitable for outdoor base station applications.