In this paper, we present a two-element circularly-polarized antenna array for UHF-band RFID reader applications. The antenna element in the array is a comer-truncated rectangular patch placed on a thick plastic-foam dielectric. The patch is fed on one of its edges by a microstrip line printed on a separate thin substrate. The array antenna is fed by a microstrip power divider. Parametric studies on the patch are carried out, from which an optimum design of a single antenna element is derived. The element spacing and the feed network of the array are investigated. A commercial electromagnetic software is employed in the analysis and design of the antenna. The designed array is fabricated and tested. Measurements show good performance characteristics of the fabricated antenna: a 11.2-dBi gain, a reflection coefficient of - 14 dB, an axial ratio less than 3 dB over 3-dB beamwidths of 40 and 60 degrees on two principal planes.