Abstract: A microwave metamaterial shelter with an electromagnetic narrow window over a broad absorption spectrum is experimentally demonstrated by resorting to conventional impedance-matching theory and metamaterial resonance. This device consists of a broad absorber and an embedded electric resonator, and has the ability of permitting one to "see" surroundings but not to be readily sensed by outside detectors. The origin is verified to be a dipole oscillation excited in absorbing region which can induce selective re-emission of the captured energy towards the enclosed space. The performance of "observing without being perceived" is numerically presented.