A small array composed of four slot elements has been investigated [Nakayama and Nakano, 1995]. This array, for which the feed system is designed using a decoupling technique, operates as a dual linear polarization antenna. The decoupling technique is found to be useful for obtaining high input port isolation. This paper presents large array antennas composed of 16 and 64 slots. Stacked and coplanar feed systems adopting the decoupling technique are fabricated to excite these arrays. The radiation characteristics of the arrays are measured and discussed.