Fe29Co71 and Fe19Ni81 antidot arrays, withdifferent dimensions, are prepared with the rf magnetron sputteringmethod onto the porous alumina substrate. The size and shape of antidotarrays are characterized by scanning electron microscopy. The glancingangle x-ray diffraction patterns of Fe29Co71 andFe19Ni81 antidot arrays indicate the bcc and fcc structures, respectively. The coercivities of both the alloys showabnormal thickness dependence, which are discussed qualitatively byconsidering the pinning and the thickness effect to the films.