ABSTRACT A filtering metal patch antenna utilizing a pair of folded metal resonators and double‐layer 2 × 2 patches is proposed for expanding bandwidth, enhancing frequency selectivity, and widening the stopband based on characteristic mode analysis (CMA). The folded metal resonator with an L‐shaped stub provides two reflection zeros when the currents on the upper and lower parts are the same. Meanwhile, an extra reflection zero can be obtained by the 2 × 2 patches excited by the folded metal re